AC: See “Ascendant”

Air sign: Gemini, Libra, or Aquarius. See “Element.”

Angle: The ascendant, descendent, midheaven, or nadir. (See those entries.) All of these are significant points in an astrological chart.

Angular: Conjunct an angle, or in one of the angular houses. The first, fourth, seventh, and tenth houses are the angular houses. See also “Cadent” and “Succedent.”

Applying: An aspect (see “Aspect”) is applying when it is still being formed, when the planets involved are moving into it. If it’s an aspect within a chart, it is applying if the faster moving planet has not yet reached the degree and minute where the aspect would be exact. If it’s an aspect by transit, it is applying when the transiting planet has not yet reached exact. See also “Separating.”

Ascendant: The point in the zodiac that was on the eastern horizon at the moment of birth, in a natal chart, or at the moment of the event in an event chart. In all house systems except whole sign, the ascendant is always the first house cusp. It is one of the most significant placements in all astrological charts. Abbreviations: AC, Asc, ASC 

Ascending node: See “North Node”

Aspect: Geometric angle between planets. Aspects are found within a chart, and are also formed temporarily by transiting planets. The primary aspects used by all astrologers are the traditional, or Ptolemaic, aspects: the trine, sextile, opposition, square, and conjunction (see the separate entries for each of those aspects). In modern astrology, other aspects are also used, such as the quincunx (see “Quincunx”), sesquiquadrate, biquintile, etc. For simplicity’s sake, I personally tend to stick with the Ptolemaic aspects, although I also look at quincunxes if they’re in the chart and relevant to the question at hand. Because I do not use any of the other modern aspects, I am not including them in this glossary.

Aspect pattern: A shape created by three or more planets forming aspects with each other at the same time. Aspect patterns can exist in a natal chart, and can be formed temporarily by a transiting planet. If any of the planets in an aspect pattern is conjunct another planet, both planets in the conjunction are part of the aspect pattern, but for the purpose of the aspect pattern, they function as one. Kind of like a multiple player card game in which one of the players is actually two people who are sharing a hand and a turn.

Asteroid: Same thing in astrology as in astronomy. While the meat of an astrological chart is the planets, asteroids can be added for additional details. They have astrological meanings of their own, but every meaning of an asteroid can also be found in the planets. Some astrologers work extensively with asteroids. I do not. I find that they don’t tell me anything I wouldn’t get from other placements in the chart, and adding asteroids makes the chart too cluttered for my liking.

Birth chart: An astrological chart cast for the date, time, and place of an individual’s birth. Used as the basis for most astrological readings. Also called natal chart.

Cadent: A cadent house, or a placement in a cadent house. The third, sixth, ninth, and twelfth houses are the cadent houses. See also “Angular” and “Succedent.”

Cardinal: See “Modality”

Chart ruler: The planet that rules the rising sign. See “Rising sign” and “Ruler.”

Chiron: Name of a specific heavenly body that is not a planet and not an asteroid but does have astrological meaning, in modern astrology, and is usually shown in astrological charts, even if asteroids are not shown. Discovered in 1977, Chiron was initially classed as an asteroid, but astronomers now consider it something else, in a class of its own, not planet or asteroid, and not a comet either, but it appears to be of the same material as the nucleus of a comet. Chiron has an erratic orbit, which crosses paths with the orbits of Saturn and Uranus, and takes approximately 50 years to complete a full cycle. Its astrological meaning is the wounded healer. Chiron in a natal chart indicates the kind of wound that you must always be in the process of healing, but healing may never be complete in a lifetime, and also the healing process.

Composite chart: A fusion of two people’s natal charts, usually created by calculating the midpoints of every placement. The composite sun is the midpoint of their natal suns, the composite ascendant is the midpoint of their natal ascendants, and so on. (See “Midpoint.”) This is done for people in a relationship, usually a couple relationship, to show what the relationship can create, and what astrological factors affect the relationship as an entity. Because an accurate ascendant for each party is necessary for a composite chart to be drawn, accurate birth details must be available for both parties. If an accurate time of birth is not available for one party, an accurate composite chart cannot be done, but composites of any of their planets except the moon can be calculated. Composite charts are not so useful in exploring how the couple experience the relationship day to day; for that, see “Synastry chart.”

Conjunct, conjunction: Together. Planets are conjunct, or in conjunction, if they are within a few degrees of each other. A planet can also be conjunct a chart point. Conjunct can also be used as a verb, to describe a transit (see “Transit”): “Mars is conjuncting my Venus.”

Cusp: The boundary between two signs or two houses.

DC: See “Descendent”

Declination: Imagine the latitude lines on a globe, transferred to the sky. That is declination. Astrological signs are measured in longitude, not latitude, so declination is not shown in the wheel chart, but ephemerises and professional astrology software programs also list the planets’ positions in declination. I do not usually use declinations in my readings, but they can provide additional information.

Descendent: The point in the zodiac that was on the western horizon at the moment of birth, in a natal chart, or at the moment of the event in an event chart. In all house systems except whole sign, the descendent is always the seventh house cusp. It is always exactly opposite the ascendant, and while usually not considered as key as the ascendant, is still a highly significant point in the chart. Abbreviations: DC, Dsc, DSC

Descending node: See “South Node”

Detriment: A planet is in detriment if it is in the sign opposite its exaltation (see “Exaltation”). This is considered a weakening factor: planets express themselves especially well in exaltation, but because the opposite sign has opposite characteristics, the planet is thought not to express itself as strongly when there. This concept is used mainly by traditional astrologers.

Direct: A planet is direct when it is moving forward in the zodiac, from our perspective. The sun and moon are always direct, and the rest of the planets are direct more often than not. Direct is their normal state, retrograde, the opposite. See also “Retrograde.”

Direction: Whether a planet is moving retrograde or direct. See those entries.

Domicile: A planet’s home sign. A planet is domiciled when it is in a sign it rules (see “Ruler”). Planets in domicile tend to be expressed in a particularly strong way. This is recognized in all forms of astrology, both modern and traditional.

Dragon’s head: See “North Node”

Dragon’s tail: See “South Node”

Earth sign: Taurus, Virgo, or Capricorn. See “Element.”

Ecliptic: The path of the sun’s orbit around the earth. No, the sun doesn’t really orbit the earth, but from an earth-based perspective, it looks like it does. For the purpose of astrology, we use this perception, although we know that what we call the ecliptic actually reflects earth’s orbit around the sun. I rarely if ever mention the ecliptic in astrology readings, but I’m including it in this glossary because the ecliptic is the basis for the astrological signs, useful for explaining why the signs are where they are, and for the nodes, which definitely come up in some of the readings I do (see “Nodes”).

Electional astrology: A method of planning using astrological factors. Electional astrology can be used to choose the best of the available dates and/or times for a wedding, a medical procedure, a grand opening of a business, or any other pre-planned event.

Electional chart: A chart cast for the purpose of electional astrology.

Element: Energetic characteristics of astrological signs, described as fire, earth, water, or air.

Ephemeris: A reference book that lists every planet’s astrological position on every date in the years it covers. Also available online. Before computers made it easy, astrologers had to look up every position in the ephemeris to cast a chart, do the calculations themselves, and draw the whole chart by hand. Although the computer will now do that for you in seconds, an ephemeris is still useful for a quick look at past or future transits, and for keeping your chart drawing skills sharp.

Equal house: A house system (see “house systems”) in which every house begins at the same degree as the ascendant. For example, if the ascendant is at 3 degrees Capricorn, every house begins at 3 degrees of its sign. The second house cusp will be at 3 Aquarius, third at 3 Pisces, etc.

Event chart: An astrological chart cast for the date, time, and place that something happened. Also used as a predictive technique: event charts may be cast for planned, and for inevitable, future events, such as the time of an eclipse, a wedding, or the inauguration of an elected leader. An event chart cast for a planned future event is an electional chart if the date and/or time has not yet been chosen and the chart is being cast to determine which would be best.

Exaltation, exalted: A concept from traditional astrology, in which planets are considered to be strengthened in certain signs, although a planet’s exaltation is, with one exception, not its domicile (see “Domicile” or “Ruler”), and not every sign has an exalted planet. The sun is exalted in Aries, the moon in Taurus, Venus in Pisces, Mars in Capricorn, Jupiter in Cancer, and Saturn in Libra. Mercury, the only exception to the rule, is both exalted and domiciled in Gemini. The modern planets, Uranus, Neptune, and Pluto, do not have exaltation signs, because exaltation is a traditional concept, and traditional astrology does not use those planets. Some modern astrologers consider Uranus to be exalted in Scorpio, but this is not a widely accepted position.

Fall: A planet is in fall if it’s in the sign opposite its domicile (see “Domicile” or “Ruler”). Being in fall is considered a weakening factor, making the planet express itself less strongly. A planet’s energies really shine when it’s in domicile, but because its fall sign has opposite characteristics from the domicile sign, it can be thought of as struggling to express itself when it’s there.

Finger of God: See “Yod”

Fire sign: Aries, Leo, or Sagittarius. See “Element.”

Fixed: See “Modality”

Focal planet: In an aspect pattern, the focal planet is the one that the aspect points to. Grand trines and grand crosses do not have a focal planet. All other aspect patterns do. (See “Aspect pattern,” “Minor grand trine,” “Kite,” “T-square,” and “Yod.”)

Glyph: The symbol used in an astrological chart for a sign, planet, point, or asteroid.

Grand cross: Also called grand square. An aspect pattern in which four planets, in four different signs, are placed so that each planet is in opposition with one of the others and square to the other two (see “Opposition” and “Square”). It does not have a focal planet. Typically, a grand cross is formed across all four signs in one modality (see “Modality”), and can be referred to by that modality: a fixed grand cross, mutable grand cross, or cardinal grand cross.

Grand square: See “Grand cross.”

Grand trine: An aspect pattern in which three planets, in three different signs, are placed so that each of them trines both of the others (see “Trine”). The grand trine does not have a focal planet. Typically, it is formed across all three signs in one element (see “Element”) and can be referred to by that element: a fire grand trine, earth grand trine, water grand trine, or air grand trine.

Horary: A branch of astrology that uses event charts and traditional predictive methods to answer specific questions. A horary chart is cast for the date, time, and place that the question is asked. If the consultation takes place online, the astrologer uses his/her own location and the time that they first understood the question. This form of astrology does not require birth information, but it does require very specific and complex skills.

House: A division of the astrological chart that represents certain areas of life. There are twelve houses, and every sign passes through all of them over a 24 hour period. While every sign is an even 30 degrees, houses can be bigger or smaller, although the average house size is also 30 degrees. Two systems of calculating houses, equal house and whole sign, make each house exactly 30 degrees. In all other house systems, the size of a house varies.

House cusp: The boundary between two houses. House cusps are numbered according to the house that begins there. The boundary between the first and second house is the second house cusp, the boundary between second and third is the third house cusp, and so on.

House system: A method of calculating where the house cusps are. There are different methods, and they usually produce slight variations in exactly where the house cusps fall, although in all house systems, the angles are in the same place.

IC: Abbreviation for nadir, from the Latin imum coeli (bottom of the sky). See “Nadir.”

Intercepted (intercept; interception): A sign is intercepted if there are no house cusps in it. This is possible in quadrant house systems (see “Quadrant system”), if a sign is in a house larger than 30 degrees, the cusp of the house is in the previous sign, and the next house cusp is in the next sign. A planet can be described as intercepted if it is in an intercepted sign.

Joy, house of joy: A concept from traditional astrology, in which each of the traditional planets is considered to be strengthened if it is in a certain house. The sun joys in the ninth house, the moon in the third, Mercury in the first, Venus in the fifth, Mars in the sixth, Jupiter in the eleventh, and Saturn in the twelfth. The modern planets, Uranus, Neptune, and Pluto, do not have houses of joy, because joy is a traditional concept, and traditional astrologers do not use those planets. Planets are not weakened if they are not in their houses of joy, they just don’t have that extra boost.

Ketu: See “South Node”

Kite: An aspect pattern that encompasses a grand trine, a minor grand trine, and an opposition (see entries for these aspects), all at once. One planet, called the head of the kite, is in opposition with another planet, and is also sextile two other planets that trine each other, forming a minor grand trine. The planet opposite the head of the kite is also trine each of the planets that sextile the head, creating a grand trine. The head of the kite is the focal planet for the whole kite.

Koch: A quadrant house system (see “Quadrant system”)

MC: Abbreviation for midheaven, from the Latin medium coeli (middle of the sky). See “Midheaven.”

Mean node: One method of calculating the position of the nodes. (See “Nodes”) Produces slightly different results, up to a degree and a half, from true node, which is the other method of calculating the nodal position. Charts are usually cast with either true node or mean node. Once in a while, both versions are shown in the same chart.

Medical astrology: A form of astrology used to help identify health conditions, using the principles of hot/cold/wet/dry found in Galenic and Chinese medicine, astrological significators of body parts, and traditional astrology techniques. Can be done with a natal chart or horary (see “Horary”). Medical astrology cannot substitute for medical advice, and it is not legal to diagnose disease that way. However, it may be useful in getting a sense of what a medical practitioner should look for, especially in cases that are difficult to diagnose.

Midheaven: The point in the sky that is directly overhead, where the sun would be at solar high noon. The midheaven in an astrological chart shows where in the zodiac that point was at the moment of birth, in a natal chart, or at the time of the event in an event chart. It is one of the most important chart points. In quadrant house systems, the midheaven is always the tenth house cusp. In whole sign and equal house systems, the midheaven is not always in the tenth house, and is usually not a house cusp, although its symbolism is the same as the tenth house’s: both represent public reputation and career. Abbreviation: MC

Midpoint: The halfway point between two chart placements. Midpoints can be calculated between two placements in the same chart (i.e. the midpoint between my sun and my moon) or they can be calculated between placements in two people’s birth charts. See also “Composite chart.”

Minor grand trine: An aspect pattern in which two planets are trine each other and a third planet sextiles both of them. The sextiling planet that is not in the trine is the focal planet. (See “Sextile” and “Trine”)

Modality: Energetic characteristics of signs based on the seasonal order they fall into. There are three modalities: cardinal, fixed, and mutable. Cardinal signs (Aries, Cancer, Libra, and Capricorn) are the signs that the sun enters on a solstice or equinox. Fixed signs (Taurus, Leo, Scorpio, and Aquarius) are the signs that anchor the season: when the sun is in a fixed sign, it is solidly spring, solidly summer, etc. Mutable signs (Gemini, Virgo, Sagittarius, and Pisces) are the signs that the sun is in when the season is shifting. The sun’s passage through a mutable sign always ends on a solstice or equinox, when it moves into the next cardinal sign.

Modern astrology: The version of Western astrology developed during its revival in the late nineteenth to early twentieth century. Modern astrology uses the same basic concepts as the older traditional astrology, but has a different focus and spins some of the concepts in a different way. While modern astrology can be used for prediction, it usually has more of a psychological focus. Modern astrology assigns astrological functions to heavenly bodies that cannot be seen with the naked eye, including the planets beyond Saturn and asteroids. It also adds aspects that traditional astrology does not use, and dispenses with some of the stricter rules of traditional astrology (a little like the difference between Orthodox and Reform Judaism). However, it’s fairly common for modern astrologers to use certain traditional techniques in certain cases.

Mutable: See “Modality”

Mutual reception: Planets are in mutual reception if each of them is in a sign ruled by the other. For example, if Venus is in Gemini and Mercury is in Taurus, that is mutual reception, according to modern astrology. Traditional astrologers add another condition: for it to be mutual reception, not only do the planets have to be in each other’s domiciles, they also have to be in a Ptolemaic aspect by sign. That would make the Venus in Gemini and Mercury in Taurus example not mutual reception, because those signs do not form a Ptolemaic aspect. However, if Venus is in Aries and Mars is in Libra, that is mutual reception by both modern and traditional definition, because those signs are in opposition. (See “Ruler” and “Aspect”)

Nadir: Opposite point in a chart from the midheaven (see “Midheaven”). In quadrant house systems, the nadir is always the fourth house cusp. In whole sign and equal house systems, the nadir is not always in the fourth house and usually not a house cusp, although its symbolism is the same as the fourth house’s: home, family, ancestry, land.

Natal: Adjective, describes a placement in the birth chart. “Natal sun” refers to the position of the sun in the natal chart, “natal Mercury” to the position of Mercury in the natal, etc. Used to distinguish a natal placement from the progressed or transiting version (i.e. “My natal sun is in Leo and my progressed sun is in Libra, and the sun is currently transiting my seventh house.”) Also used to describe the field of astrology that deals with birth charts: natal astrology, distinct from horary, predictive, or electional astrology. Natal can also be used as shorthand for “natal chart.”

Natal chart: See “Birth chart.”

Native: The person whose natal chart we’re talking about, when we’re talking about someone’s natal chart.

Nodes: The two points on the ecliptic (see “Ecliptic”) where the sun’s “orbit” and the moon’s actual orbit around the earth cross each other. Most of the time, the moon is either just north or just south of the ecliptic, keeping it from crossing paths exactly with the sun. Twice a month, roughly two weeks apart, the moon crosses the ecliptic, moving north when it crosses the north node and south when it crosses the south node. Twice a year, roughly six months apart, the sun’s path takes it over one of the nodes. During the months in which that occurs, the moon crosses the ecliptic at the very same node the sun is on when it is new, causing a solar eclipse, and on the opposite node from the sun when it is full, causing a lunar eclipse. Astronomers use the nodes to predict eclipses, and astrologers use them as important chart points with certain functions. See “North Node” and “South Node.”

North Node: The node (see “Nodes”) that the moon crosses when it’s moving north of the ecliptic. Also called rising node, ascending node, dragon’s head, or Rahu. The north node in a natal chart represents where you’re going in your lifetime, what you need to bring into your life overall, karmic lessons to learn. It also has the effect of making the energy of any planet near it bigger, more apparent in the material world. In Hindu mythos, the north node is Rahu, the dragon’s head with no body. Not having a stomach, Rahu can never be satisfied, so the north node is voracious, always wanting more of whatever it is near.

Opposition: An aspect of 180 degrees, give or take up to 5-10 degrees. Planets in opposition are typically in signs that fall directly opposite each other in the zodiac, six signs apart. Opposite sign pairs are in the same same modality (see “Modality”) but different elements (see “Element”).

Orb: The number of degrees away from exact an aspect is, or how far from exact it can be and still be considered an aspect. Most trines are not an exact 120 degrees, most squares are not an exact 90 degrees, and so on. The aspect still exists if it’s a few degrees more or a few degrees less. However, astrologers differ on how wide an orb an aspect can have before it is no longer an aspect. Most astrologers count natal aspects with up to a five degree orb, and some still count the aspect if the orb is as much as ten degrees, especially if it involves the sun and/or the moon. Some astrologers only use narrow orbs, and will no longer count it after 2 or 3 degrees. For transiting aspects, usually the narrower orb is used.

Peregrine: If a planet is in a sign that neither weakens it nor strengthens it, it is peregrine. See “Domicile,” “Fall,” “Exaltation,” and “Detriment” for definitions of signs that weaken or strengthen planets. Peregrine planets have no trouble expressing themselves through the sign they’re in, unlike planets in fall or detriment, but do not get the extra boost that they would get from being domiciled or exalted.

Placidus: A quadrant house system (see “Quadrant system”). The default house system used in most online chart casting programs. It is the one I currently use the most.

Planet: Come on, you know what a planet is! Same thing in astrology as in astronomy. There is a difference, though: in astrology, the sun and moon are planets, but the earth is not. While every astrologer knows that the sun and moon are not planets, scientifically speaking, and only the moon revolves around the earth, astrology is based on what it looks like, not what it really is. In astrology, we act as if the earth were the center of the universe, which makes a planet one of those things that revolves around us. Astrology is an art, and as Picasso said, art is a lie that tells the truth.

Point: Any piece in an astrological chart that is not a planet, and not a physical heavenly body of any kind, but does have a placement by sign and degree. The angles and nodes are points.

Polarity: The yin or yang quality of a sign. More often called feminine or masculine by Western astrologers. Water signs (Cancer, Scorpio, and Pisces) and earth signs (Taurus, Virgo, and Capricorn) are yin. Fire signs (Aries, Leo, and Sagittarius) and air signs (Gemini, Libra, and Aquarius) are yang.

Porphyry: A hybrid quadrant/equal house system (see “House system”) in which the angles (see “Angles”) are used as first, fourth, seventh, and tenth house cusps and the spaces between them are divided into equally sized houses. That makes every house in the same quadrant (quarter of the circle) the same size, but the quadrants can be different sizes from each other, so not all the houses in the chart are equal.

Progression: A technique in which the planets in the birth chart are moved to new positions. The most commonly used version is secondary progressions, in which a day equals a year. Your progressed chart is the chart that matches what was in the sky when you were however many days old equals however many years old you are now. For example, if you’re 35, your progressed chart is the chart for when you were 35 days old. The next most common version is solar arc progressions, in which the sun is progressed the same way as in secondary progressions and all other planets are moved forward in the zodiac at the same rate as the sun. This results in all progressed planets moving roughly one degree a year. Progressed charts, secondary or solar arc, are not used all by themselves, but overlaid with the natal chart as a predictive technique. Themes turning up in progressions, and in the progressed chart’s interaction with the natal, reflect significant life themes and events, and themes related to transits are more likely to manifest in a noticeable way if they’re echoed in progressions.

Quadrant system: Any method of calculating house cusps (see “house system”) that is not whole sign or equal house. Quadrant systems are, basically, mathematical calculations of where the house cusps really fall, given the curvature of the earth at a specific location. At the equator, all quadrant systems produce equal 30 degree houses, all the time. Everywhere else, quadrant systems produce houses of varying size, although they may be practically equal at certain times of day and year. The variance is greatest at high latitudes. There is one hybrid quadrant/equal house system, Porphyry (see “Porphyry”).

Quincunx: An aspect of 150 degrees, give or take 2-3 degrees (I know of one astrologer who uses up to 8 degree orbs for quincunxes, but most do not consider it a quincunx if it’s more than 2 or 3 degrees from exact). Planets in quincunx are typically five signs apart, in signs that are both different elements (see “Element”) and different polarities (see “Polarity”). This aspect is used by modern astrologers only. All other aspects defined on this page are used by both modern and traditional astrologers.

Rahu: See “North Node”

Retrograde: A planet is retrograde when it’s moving backward in the zodiac, from our perspective. The sun and moon cannot go retrograde, but all other astrological planets can. In astrological charts, retrograde planets are usually indicated with an “R” or “Rx” placed next to their glyph like a footnote.

Return: When a transiting planet returns to the exact degree and minute where it is in the natal chart.

Rising node: See “North Node”

Rising sign: The sign the ascendant is in (see “Ascendant”)

Ruler: Each sign is ruled by a planet. Each house is ruled by the planet that rules the sign its cusp is in. Similar to a landlord, who has say over the home he owns, the planetary ruler of a house has a strong effect on the matters represented by that house. The sun rules Leo, the moon rules Cancer, Mercury rules Gemini and Virgo, Venus rules Taurus and Libra, Mars rules Aries and (traditionally) Scorpio, Jupiter rules Sagittarius and (traditionally) Pisces, and Saturn rules Capricorn and (traditionally) Aquarius. Modern astrology adds Pluto as the ruler of Scorpio, Uranus as the ruler of Aquarius, and Neptune as the ruler of Pisces. Some modern astrologers (self included) use both modern and traditional rulers, treating them as co-rulers. Others replace traditional with modern. Still other modern astrologers, and all traditional astrologers, use traditional rulers only. None of the other signs have a modern ruler, so for those, the original ruler is always used.

Separating: An aspect (see “Aspect”) is separating when it has already perfected and the planets involved are moving out of it. If it’s an aspect within a chart, it is separating if the faster moving planet has already passed the degree and minute where the aspect would be exact. If it’s an aspect by transit, it is separating when the transiting planet has already passed exact. See also “Applying.”

Sextile: An aspect of 60 degrees, give or take up to 5-10 degrees. Planets in sextile are typically two signs apart, in signs that are the same polarity (see “Polarity”) but different elements (see “Element”). Also used as a verb: “Mercury sextiles Mars in this chart,” “Saturn is sextiling my sun.”

Solar Return chart: A chart cast for the moment when the sun returns to the exact degree and minute where it is in the natal chart. Happens on the native’s birthday, give or take a day or two. The solar return chart is used as a predictive tool for looking at the year ahead. Also called solar revolution. Abbreviation: SR.

South Node: The node (see “Nodes”) that the moon crosses when it’s moving south of the ecliptic. Also called descending node, dragon’s tail, or Ketu. The south node in a natal chart represents the karmic past, where you’re coming from: past lives, either literal or figurative, ancestral past, unconscious beliefs and patterns absorbed from your family and culture. It also has a shrinking effect on any planet near it. Planets at the south node can have their energy diminished, in a way, kind of like a faucet that leaks every time you turn it on: no way to get water from it without wasting some. In Hindu mythos, the south node is Ketu, the dragon’s tail separate from the head (the dragon had been cut in half). Not having a mouth, Ketu cannot take anything in, only excrete it. The south node is not always shown in astrological charts, but it is always directly opposite the north node, so can be located even if only the north node is shown.

Square: An aspect of 90 degrees, give or take up to 5-10 degrees. Planets in square are typically three signs apart, in signs that are the same modality (see “Modality”) but different polarities (see “Polarity”). Also used as a verb: “Saturn squares Mercury in this chart,” “Neptune is squaring my sun.”

Station, stationing, stationary: When a planet is changing direction (see “Direction,” “Direct,” and “Retrograde"), it slows to a standstill. That standstill is its station. When a planet is in station, it is stationing, or stationary. If the stationary planet is turning from direct to retrograde, it is stationing retrograde. If it is turning from retrograde to direct, it is stationing direct.

Stellium: Several planets in the same sign or house. By the traditional definition, it has to be at least four planets, at least two of which are not the sun, Mercury, or Venus, in order to be called a stellium. Modern astrology has a more relaxed definition: at least three planets in the same sign or house, and they can be any combination of planets. However, some modern astrologers prefer the traditional definition when it comes to stelliums.

Succedent: A succedent house, or a placement in a succedent house. The second, fifth, eighth, and eleventh houses are the succedent houses. See also “Angular” and “Cadent.”

Synastry chart: A biwheel in which two people’s birth charts are placed together, one inside the other. This is used to explore the relationship between two individuals, and the dynamics between them. It is also possible to compare more than two charts at a time this way, although that is much more complex, not all astrologers do it, and not all astrology software programs allow for it. If time of birth is unknown for one of the parties in the relationship, a synastry chart can still be cast, although it will not show accurate houses for the one with the unknown birth time, and the placement of their moon may not be accurate.

Traditional astrology: The version of Western astrology based on traditional practices, developed before the invention of the telescope. Traditional astrology does not use any of the planets beyond Saturn, does not use asteroids, and does not use any aspects other than the conjunction, sextile, square, trine, and opposition (see entries for these aspects). Its focus is on prediction, not personality assessment. Traditional astrology includes a number of complex predictive techniques, and many rules and concepts that modern astrology either relaxes or dispenses with.

Transit: The movement of a planet through the zodiac. When a transiting planet forms a conjunction to a natal planet, it is said to be transiting that planet. A planet may also be described as transiting the sign it is moving through (i.e. “Saturn is currently transiting Capricorn”) or a house (“Saturn is transiting my first house.”) If a transiting planet forms an aspect, i.e. square, to a natal planet, that could also be called transiting, but it is typically called by the name of the aspect, used as a verb: “Saturn is squaring my moon.” If a transiting planet forms a conjunction to its own position in the natal chart, that is a return (see “Return”).

Trine: An aspect of 120 degrees, give or take up to 5-10 degrees. Planets in trine are typically four signs apart, in signs that are the same element (see “Element”). Also used as a verb: “Sun trines Moon in this chart,” “Uranus is trining my Venus.”

Triple conjunction: Three planets all in conjunction with each other. See “Conjunction.” Also might be called a stellium, by the modern definition (see “Stellium”).

True node: One method of calculating the position of the nodes. (See “Nodes”) Produces slightly different results, up to a degree and a half, from mean node, which is the other method of calculating the nodal position. Charts are usually cast with either true node or mean node. Once in a while, both versions are shown in the same chart.

T-square: An aspect pattern in which two planets are in an opposition and a third planet squares both of them. The squaring planet is the focal planet. (See “Square” and “Opposition”) Typically, all signs involved are in the same modality (see “Modality”). If a fourth planet were in opposition with the focal planet, the t-square would become a grand cross (see “Grand Cross”).

Water sign: Cancer, Scorpio, or Pisces. See “Element.”

Wheel chart: The form of astrology chart most widely used today. If you’ve ever had your birth chart done, it was pretty definitely a wheel chart. The charts I use in Ask the Astrologer are wheel charts. Fun fact: the first computer program to generate wheel charts was designed by Joan Quigley, astrologer to Ronald Reagan, the only U.S. president known to have consulted one.

Whole sign: A house system (see “house system”) in which each sign equals a house. The sign the ascendant is in is the first house, the next sign is the second house, etc. Whole sign is the only house system in which the ascendant and descendant are not the cusps of the first and seventh houses, respectively, unless they are exactly at degree 0 of their signs. It is also the only house system in which sign and house are the same.

Yod: Also called Finger of God. An aspect pattern in which two planets are in sextile and a third planet is quincunx both of them. The planet that forms the quincunxes but is not in the sextile is the focal planet. (See “Quincunx” and “Sextile”)