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When two or more factors in a chart are linked in a harmonious way, such as planets placed in complimentary signs.



The four directions in a chart, marked by the beginning cusp of the first, fourth, seventh, and tenth houses as calculated by four points where the horizon or meridian intersect the ecliptic at the time and place of birth.



A planet may be referred to as angular if it is in one of the four angular houses (first, fourth, seventh, or tenth) and/or conjunct one of the four angles.



A term used to designate when an aspect is pre-exactitude. Also called approaching.



An idea or concept that resides in the collective unconscious, which is universally present in each individual’s subconscious without having necessarily learned it consciously; a primal symbol.


Ascendant (see also Rising Sign)

The first of the four angles of the chart which marks the four directions in most house systems. The Ascendant is the precise point at which a particular degree of a zodiac sign intersects with the ecliptic at the moment of birth, as differentiated from the Rising Sign, which refers to the entire sign in which the Ascendant is contained. The terms Rising Sign and Ascendant are often used interchangeably for convenience.



The angular relationship between two planets or points as measured in arc (degrees apart) in a chart.


Aspect Pattern

An aspect involving more than two planets, each in specific relationship to each other and often crossing over the entire chart.



Planetary-like objects (sometimes called planetoids) found primarily in the asteroid belt located between Mars and Jupiter that maintain orbit around the Sun as a planet does. Asteroids are part of a larger group called minor planets, which includes dwarf planets (such as Ceres and the reclassified designation of Pluto as of 2006), centaurs (bodies in orbit between Jupiter and Neptune) and trans-Neptunian objects (those orbiting beyond Neptune, which yes, also includes Pluto). 


Some astrologers incorporate asteroids into an astrological chart and seek to interpret their meaning in the same manner as the planets. Popularly used asteroids in astrology include (among others) Ceres, Juno, Pallas-Athene, Vesta. Pluto is still considered a planet in most astrological references as far as its relevance.



The study of the heavens as they relate symbolically to events and people on earth.


Astrology, Types of

Many different astrological systems and uses have been imagined over time. Here are a few, though not all:


Chinese astrology – A system altogether different from western/tropical astrology. 12 signs make up the zodiac of this system, and are not connected to constellations along the ecliptic. They are: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, and Pig. One’s birth year, month, day, and hour, referred to as the Four Pillars, has a correspondence with one of the twelve animals, with the maximum possibility of four different animals representing an individual’s character or destiny. 


Electional astrology – The use of astrology to determine the most favorable moment and place to ‘birth’ something, such as a business, a marriage, or even a child. 


Horary astrology – The use of astrology to determine the answer to a specific question by casting a chart for the exact time and place of the question as it is asked.


Jyotish astrology (also referred to as Hindu, Indian, and Vedic astrology) – Another system which differs from Western astrology. Jyotish employs the same 12 signs but defines them according to sidereal coordinates. It also incorporates a further division of the sky into 27 sections, called lunar mansions, and utilizes 16 elements.


Mayan astrology – An astrological system differing from Western in that it utilizes 20 signs, some animals, some objects, and some concepts or events such as death or wind. Mayan astrology also uses directions instead of elements and a 260-day year calendar called the Tzolkin.


Medical astrology – The use of astrology to analyze one’s physical health from an individual’s natal chart. Each sign (and in some applications, planet too) corresponds with a few specific areas of the body.


Mundane astrology – The use of astrology to analyze world affairs and events, including political analyses. The astrology of places.


Natal astrology – The use of astrology to study the makeup of an individual from many angles, including psychological, spiritual, emotional, and biographical.


Sidereal astrology – A method of defining the zodiac sign boundaries. The use of the zodiac of 12 signs based on the fixed stars of the constellations that lie along the ecliptic rather than the designated sections of sky which begin with the point of the vernal equinox (tropical).


Tropical astrology – A system so called for it’s method of defining the zodiac sign boundaries. The tropical astrology use of the zodiac of 12 signs based on the declination of the sun as it moves between the tropics of Cancer and Capricorn, as differentiated from the alignment of the constellations of the same names (sidereal).



The study of the universe and celestial objects including analysis of their positions, movements, composition and origin.



The measurement around the circumference of a circle. The length of a given arc is a measurement of a portion of a circle. 



An imaginary line drawn through the center of the earth (or any planet) between the poles, about which the planet rotates or ‘spins’.



An ancient term which refers specifically to a planet or aspect that is seen as beneficial, good, or favorable, typically Venus or Jupiter.


Celestial Sphere

As earth is surrounded by infinite space, the celestial sphere is an imaginary sphere meant to represent the universe surrounding the earth in every direction, with earth at the center.



In Astrology, the two-dimensional representation (“map”) of the heavens at a moment in time. 



A defined area of the celestial sphere containing a set of stars, or star pattern, that has been given a name, which varies according to cultures and time period.


Contraparallel (see also Declination)

A less well-known aspect between two or more planets which is based on their declination, their latitudinal distance from the celestial equator. When two planets are found in the same degree (typically with a 1º orb allowance) on opposite sides of the celestial equator (one north and one south) they are contraparallel to each other. This aspect is often interpreted as a ‘weaker’ opposition.



The boundary that separates one sign or house from the next.


Debility (see also Dignity)

Refers to a planet located in a sign that is considered its Fall or Detriment. 



The division of each of the twelve signs into three equal parts, measuring 10º each.



The distance of a planet or point from the celestial equator, north or south, as measured by degrees, minutes, and seconds of arc.


Degree (see also Arc)

A unit of measurement. A circle is measured in even 360 portions, each one called a degree.



A term used in astrology to refer to the chart interpretation process, more specifically to interpreting the combining of any two chart components, such as a planet in a sign or an aspect between two planets.



The third of the four angles of the chart which marks the four directions in most house systems. The Descendant is the precise point at which a particular degree of a zodiac sign intersects with the ecliptic at the moment of birth on the western side.



A term used to measure the strength or prominence of a planet by its placement in a chart. When a planet is placed in a sign that is considered beneficial to the expression of the planet according to ancient designations, that planet is in essential dignity. There are five essential dignities: Domicile (vs. Detriment), Exaltation (vs. Fall), Triplicity, Terms, and Face (Decanate).


A planet in accidental dignity refers to how prominent that planet is because of how it is placed in the context of the whole chart. A planet’s influence may be greater in a chart because of a number of reasons, including (but not limited to): being placed in a prominent location (such as in a house containing one of the four angles) or having great neighbors, such as in a favorable aspect to a benefic planet.



A term used to describe the apparent forward motion of a planet in its orbital path, as opposed to retrograde, which is apparent backward motion.



A planet which rules the sign on the cusp of any house or planetary placement in a chart. For example, Taurus on the second house cusp would defer to Venus, because Venus rules Taurus. Mars in the sign of Taurus in a natal chart would also defer to Venus for the same reason. The word comes from the Latin word meaning “to put in different places.” A planet which rules the sign on a house cusp or that rules the sign any other planet is in is said to move or carry the energy forward around the chart. 



A category in which the twelve signs are divided into two groups: Projective and Receptive, also commonly called Masculine and Feminine or Positive and Negative.



The temporary occurrence of a planetary body obscuring another planetary body, such as the sun’s light obscured by the moon when viewed from earth or the reflected light from the moon when the earth lies between the sun and moon. This phenomenon can only occur in total when all three bodies align at the same (total eclipse) or near the same (partial eclipse) declination. The blocked planetary body can either be obscured by another planetary body moving in front of it (from our perspective on earth) or by passing through another planetary body’s shadow.


A solar eclipse, when the sun’s light is blocked, occurs when the position of the moon is such that it stands between the earth and the sun, blocking our view of the sun (an occultation). A lunar eclipse, when the sunlight which reflects off the moon is blocked, happens when the position of the earth is such that it stands between the moon and sun, with the shadow of the earth falling over the moon.



The apparent path of the sun as it appears, from the viewpoint of earth, to travel across the celestial sphere over the course of a year.



In astrology, the classification of each sign and house into four elemental categories: fire, earth, air, or water. Three signs and three houses are assigned to each of four elements and share certain qualities among others in their elemental group. 



A set of tables listing the position of the planets (including the sun and moon and sometimes the north node of the moon and select asteroids). The planet’s position is given in degrees, minutes, and sometimes seconds of the sign the planet is in at the time, of the planets at the same time each day, once a day over a period of months or years. Standard ephemerides list a planet’s position once a day, at either noon each day or midnight each day, for a period of 50 years. Astrologers use this data to track the position, apparent direction, and average speed of a planet as it moves through the signs in its orbital path along the ecliptic. This data is also used to calculate an astrology chart and is programmed into chart calculation computer programs.



The moment, occurring twice each year, when the length of the day and night are approximately equal. More technically, when the sun is at one of the two points where the ecliptic and celestial equator intersect. The equinox points mark the beginning of the signs Aries and Libra.


Fixed Star

A star that does not appear to move in relation to the other celestial bodies, such as asteroids, comets, and planets. The word planet comes from the Greek phrase which means ‘wandering star.’


Geocentric (see also Heliocentric)

An astronomical reference to the earth as the center of the solar system or something viewed from the position of the earth.



A set of symbols used as a kind of shorthand to represent the planets, signs, and aspects. 


Great Circle

A plane which slices through the center of a sphere, such as the earth and surrounding celestial sphere, dividing it.


Heliocentric (see also Geocentric)

An astronomical reference to the Sun as the center or the solar system or something viewed from the position of the Sun (helios=sun).



Half of a sphere, dividing the earth and celestial sphere into north and south hemispheres and east and west hemispheres.



In common usage, the visible boundary separating earth and sky. This is the apparent horizon, however; the true or rational horizon passes through the center of the earth.



In common, popular reference, a term referring to brief personality descriptions or predictions for a person according the sign position of the sun’s during their birth. More accurately, this term refers to one’s personal and entire natal astrology chart.



One of twelve sections which divide a natal chart, calculated according to the rules of an established house system. Each house represent a category of experiences, activities, and behaviors that everyone encounters in life.


House System

A set of principles and mathematical calculations by which the houses cusp positions are calculated in an astrological chart, including but not limited to the Placidus, Porphyry, Koch, and Whole house systems.


Imum Coeli (see Nadir)


Inferior (vs. Superior)

Planets that are closer to the sun than earth (Mercury and Venus) are inferior planets. This term is not a value judgment but refers to their inside position in the solar system. The term inferior is most often used in the phrase inferior conjunction, which refers to a conjunction of planets that is occurring on the same side of the sun as the earth.



In astrology, most often referring to the moment a planet enters a sign. It can also refer to a heavenly body crossing in front of another heavenly body (such as Mercury crossing in front of the Sun or the occurrence of a solar or lunar eclipse) from one’s viewpoint.



A birth place of extreme north or south latitude can create an interception, which happens when a given house in an astrology chart is wider than 30 degrees, engulfing its sign within that house’s borders entirely. Alternately, a given house that is narrower than 30 degrees can be engulfed within the nearest sign’s boundaries. This results in two house cusps occurring in the same sign, or a house cusp skipping a sign entirely.



Astrologically, a keyword is a word that is used frequently to describe a characteristic, trait, or behavior of an astrological symbol such as a planet, sign, or house.



On earth, distance as measured north or south from the equator. Celestial latitude is distance measured north or south of the ecliptic.



On earth, distance as measured east or west from the prime meridian. Celestial longitude is distance measured eastward from the vernal equinox point (where the celestial equator and ecliptic intersect).



A term sometimes used to describe the sun and moon.


Major Aspects (see Ptolemaic Aspects)



An ancient term which refers specifically to a planet or aspect that is seen as harmful, bad, or unfavorable, commonly as Mars and Saturn.


Medium Coeli (see Midheaven)



A Latin phrase which means “middle of the sky,” it is the point where the ecliptic and the meridian cross in the visible sky above the birth place and is associated with the 10th house in an astrology chart.



The shortest distance around the circle of the natal chart between two planets or points.


Minor Aspects

An angle between two or more planets in an astrology chart that is not defined as a Major, or Ptolemaic aspect, including (but not limited to) the Quincunx, Sesquisquadrate, and Semi-Sextile.



Three categories: Cardinal, Fixed, and Mutable, which divide the signs into groups according to broad characteristics they share. Also sometimes called qualities or quadruplicities.


Mutual Reception

Two planets which reside in each other’s sign of rulership, such as the Sun in Aries and Mars in Leo. 



Defined as the “lowest point,” the Nadir is associated with the 4th house in an astrology chart. Astrologically, it refers to the point where the ecliptic and meridian meet beneath the earth in relation to the birth place. Astronomically, it is the point directly beneath the observer and directly opposite the Zenith.


Natal Chart

A circular representation of the celestial sphere with the location of planets, sign and house divisions, and calculated points depicted at the time and place of birth. 



A term used to reference a natal chart.



Astrologically, a point in the celestial sphere where a planet crosses the ecliptic. Two calculation methods of nodes are in popular use: the mean node uses a calculation which averages out the “wobble” in earth’s rotation (see precession of the equinoxes); the true node uses a calculation which accounts for this wobble.



The allowable distance between two planets that are in aspect but are not exact. For example, two planets that are three degrees apart from each other would be a conjunction, with an orb of 3 degrees.



Astronomically, the path of a planetary body around another, such as the planets around the sun, or the moon around the earth. 



A planet that travels outside of the bounds of the ecliptic, north or south, as it orbits.


Parallel (see also Declination)

A less well-known aspect between two or more planets which is based on their declination, their latitudinal distance from the celestial equator. When two planets are found in the same degree (typically with a 1º orb allowance) and on the same side of the equator, (both north or both south) they are parallel to each other. This aspect is typically interpreted as a ‘weaker’ conjunction.



From the Latin word meaning ‘foreign’, this term primarily and originally refers to a planet has no dignity in its placement in a chart—it is not in a sign it rules, nor a sign in which its exalted, etc. Astrologer Noel Tyl has used the term in reference to planets that do not participate in one of the five Ptolemaic aspects.


Phases, Lunar

Designations assigned to the portions of the moon that is illuminated by the sun’s light (as seen from earth), which changes cyclically according to the moon’s orbit. The phase designations are somewhat arbitrary as the moon’s light cycle could theoretically be divided into any number of parts of the whole, but the most common phase system in western astrology is the eight-phase system. The eight-phase system is comprised of the following stages: new, crescent, first quarter, gibbous, full, gibbous (sometimes called disseminating), last or third quarter, and crescent (sometimes called balsamic).


For further clarification, the term waxing is applied to the crescent, quarter, and gibbous phases to designate when the illumination of the moon is increasing toward full, and waning when decreasing toward new.


Phases, Planetary

The lunar phase designations are mainly applied to the lunar light cycle, but are also applied in slightly different ways to planetary positions. Just as the lunar phases are determined by the relative position of the moon to the sun (as viewed from earth), so each planet has a position relative to each other planet. Any given planet has a phasal relationship with any other planet, even if it is not one of the designated aspects. The phase between planets is determined by starting from one planet’s position and counting degrees onward in a clockwise motion from that planet to another planet.



From a Greek phrase meaning “wandering star.” In casual reference astrologically, the term also includes the sun and moon.


Planet, Inner

Astrologically, a term which refers to the planets Mercury, Venus, and Mars, also sometimes called personal planets. The sun and moon may also be included in these phrases.


Planet, Outer

A term which refers to the three planets which outside of the seven visible planets: Uranus, Neptune, and Pluto. These are also sometimes called transpersonal planets because of their exceptional distance from the center of the solar system or modern planets because they were discovered long after the practice of astrology was established. They may also be referred to as invisible planets, as opposed to the seven visible planets.


Planet, Visible

A term referring to the ‘original’ seven planets (including the sun and moon) before the inclusion of Uranus, Neptune, and Pluto.


Planet, Social

A term which refers to the two ‘middle’ planets, Jupiter and Saturn.



A casual term to refer to any significant astrological component that is not represented by a physical body, such as the nodes. 



Signs which are located on the opposite side of the zodiac circle are said to be polarities.


Precession of the Equinoxes

A nontechnical term used to refer to the continuous change in the orientation of the earth’s axis relative to the celestial sphere. If earth’s axis is imagined to extend out onto the celestial sphere, it would point to a certain location. The place in the heavens to which this extended axis ‘points’ changes slowly over time in a repeated pattern which takes approximately 26,000 years to complete. Like a toy top that has begun to wobble slightly, the earth also ‘wobbles’ and its axis subsequently traces a small, imaginary circle in the heavens. Also called axial precession.


Ptolemaic Aspects

A term usually in reference to a group of aspects: conjunction, sextile, square, trine, and opposition, also called major aspects. The term refers to Claudius Ptolemy, a first century astrologer/astronomer who described these aspects in his influential work, Tetrabiblos.



A fourth of a circle. The natal chart is divided into four quadrants, with three houses comprising each quadrant. The first quadrant is comprised of houses 1-3, the second quadrant houses 4-6, etc.



A process or set of processes to determine the likely time of birth by comparing significant events in the biography to the motion of the planets at the time of those events.



The appearance of a planet moving backward through its orbital path as viewed from earth. The more accurate term for this is apparent retrograde motion, since the planets do not actually change direction but only appear to.


Rising Sign (see also Ascendant) 

The sign that was rising over the eastern horizon at the time of birth is known as the Rising Sign, which contains the Ascendant.


Ruler, Chart

The planet that rules the sign of the Ascendant and/or a planet that is located in close proximity to the Ascendant.


Ruler, Planetary

The planet that is said to express itself most seamlessly through a certain sign and therefore ‘at home’ in that sign is said to be its ruler. The original assignment of planet-sign rulerships included only the visible planets and was constructed not strictly according to affinity but assigned according to a pattern, fanning out from the luminaries. 



A term used to designate an aspect that is post-exactitude, that is, as the planets move further away from each other, they are separating from each other with a continually widening orb or arc between them.



One of twelve sections which circle the edge of a natal chart, correlating with the 30 degree section of sky that lies along the band of the zodiac. Each sign represents certain archetypal traits and characteristics.



The state of a planet when it appears to stop in its orbit before changing directions.



A group of three or more planets in close conjunction with each other, all in the same sign or house.


Sun Sign

A term used to refer to the sign in which the Sun was found at the time of birth. This is often simplified in popular use to simply ‘sign’, as in “What’s your sign?”



The point directly above the observer in the celestial sphere.



A circle, or narrow band, which lies along the ecliptic (the apparent path of the sun) and is divided into twelve equal sections (signs). 



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