Astrology glossary

Plain definitions of the astrology and numerology terms you'll meet in a chart — from ascendant to void-of-course moon, life path to personal year.

A

Angular houses: The 1st, 4th, 7th and 10th houses, which begin at the four angles of the chart. Planets here are traditionally considered the most visible and active.
Ascendant (rising sign): The zodiac degree rising on the eastern horizon at the moment and place of birth. It describes first impressions and approach to life, and it starts the 1st house. Read more
Aspect: An angle between two planets or points, measured along the zodiac. The major aspects are the conjunction (0°), sextile (60°), square (90°), trine (120°) and opposition (180°).

B

Big three: Your sun, moon and rising signs together — the usual quick summary of a chart. Sun is core identity, moon is emotional life, rising is how you meet the world.
Birthday number: The day of the month you were born, reduced to one digit (11 and 22 are usually kept). It is read as a specific gift that supports your life path. Read more

C

Cadent houses: The 3rd, 6th, 9th and 12th houses, which come before the angles. They are linked with learning, adjustment and preparation.
Chart ruler: The ruling planet of the rising sign. Its sign, house and aspects are read as a key thread through the whole chart.
Chiron: A small body orbiting between Saturn and Uranus, discovered in 1977. Astrologers read it as a sensitive spot that, once understood, becomes a source of empathy and skill.
Composite chart: A single chart for a relationship, built from the midpoints between two people's planets. Where synastry compares two people, the composite describes the relationship itself.
Conjunction: Two planets at or near the same degree (0°). Their energies blend and act together, for better or louder.
Cusp: The boundary line where a house or sign begins. People born near the change of sun signs are often called "born on the cusp", but the Sun is always in one sign or the other.

D

Decan: One of three 10° slices of each sign. Each decan has a sub-ruler, which astrologers use to add nuance to a placement.
Descendant: The point directly opposite the ascendant, setting on the western horizon at birth. It opens the 7th house and is read for partnerships and what we look for in others.
Dignity (domicile, exaltation, detriment, fall): How comfortable a planet is in a sign. It is strongest in the sign it rules (domicile) or its exaltation, and weakest in the opposite signs (detriment and fall).

E

Eclipse: A solar eclipse happens at a new moon and a lunar eclipse at a full moon, when they fall near the lunar nodes. They come in seasons about every six months and are read as turning points.
Element: One of four groups of three signs each: fire (Aries, Leo, Sagittarius), earth (Taurus, Virgo, Capricorn), air (Gemini, Libra, Aquarius) and water (Cancer, Scorpio, Pisces). Element describes a sign's basic temperament.
Ephemeris: A table of where the Sun, Moon and planets are at given dates and times. Astrology software calculates charts from an astronomical ephemeris.
Expression number (destiny number): The sum of all the letters in your full birth name, using Pythagorean values (A=1 … I=9, repeating), reduced to one digit or a master number. It describes natural talents and how you express them. Read more

F

Full moon: The phase when the Moon is opposite the Sun and fully lit, about 14.8 days after the new moon. Traditionally a time of culmination, visibility and release. Read more

H

House system: The method used to divide the chart into twelve houses. Placidus, Koch, equal and whole sign are common; they can place a planet in different houses.
Houses (1–12): Twelve divisions of the chart, each tied to an area of life: 1 self, 2 money, 3 communication, 4 home, 5 creativity and romance, 6 work and health, 7 partners, 8 shared resources, 9 travel and beliefs, 10 career, 11 friends, 12 the hidden. Planets in a house show where their themes play out.

I

Imum coeli (IC): The lowest point of the chart, opposite the midheaven. It opens the 4th house in most house systems and is read for home, family and roots.
Ingress: The moment a planet enters a new zodiac sign. The Moon makes an ingress every two to three days; the outer planets only every 7 to 30 years.

L

Life path number: The core number in numerology, from the full birth date: reduce month, day and year to single digits, add them and reduce again, keeping 11, 22 and 33. Read more
Lunar nodes: The two points where the Moon's orbit crosses the Sun's path. The north node is read as a direction to grow toward, the south node as familiar habits; they move backward through the zodiac in about 18.6 years.
Lunation: One full cycle of the Moon's phases, from new moon to new moon, averaging 29.53 days. The word is also used for the new or full moon itself.

M

Master numbers (11, 22, 33): The double-digit numbers 11, 22 and 33, which numerology keeps unreduced. They are read as heightened versions of 2, 4 and 6, with more potential and more pressure.
Mercury retrograde: Mercury's apparent backward motion, three or four times a year for about three weeks each. Traditionally linked with mix-ups in communication, travel and technology — a time to revise and double-check. Read more
Midheaven (MC): The point where the ecliptic crosses the meridian overhead in a birth chart, from the Latin medium coeli. It marks career direction, reputation and public life, and needs an accurate birth time. Read more
Modality (quality): One of three groups of four signs: cardinal (Aries, Cancer, Libra, Capricorn) start things, fixed (Taurus, Leo, Scorpio, Aquarius) sustain them, mutable (Gemini, Virgo, Sagittarius, Pisces) adapt and change them.
Moon sign: The sign the Moon was in at birth. It describes emotional needs, instincts and what feels comforting; the Moon changes sign about every 2.5 days, so birth time can matter. Read more

N

Natal chart (birth chart): A map of where the Sun, Moon and planets were at the exact moment and place of birth, set in the zodiac signs and the twelve houses. It needs date, time and place of birth. Read more
New moon: The phase when the Moon sits between Earth and Sun and its lit side faces away from us. It begins the lunar cycle and is traditionally a time for intentions and fresh starts. Read more

O

Opposition: An angle of 180°, between opposite signs. It describes a pull between two sides that often shows up through other people, with balance as the goal.
Orb: How far from exact an aspect can be and still count, in degrees. Tighter orbs mean a stronger aspect; many astrologers allow about 6–8° for major aspects.

P

Personal month and personal day: Finer cycles inside the personal year: add the calendar month to your personal year for the personal month, then the calendar day for the personal day, reducing each time.
Personal year number: Your birth month and day added to the current year, reduced to 1–9. It runs in a nine-year cycle: 1 is for new starts, 9 for completion. Read more
Personality number: The sum of the consonants in your full birth name, reduced to one digit or a master number. It describes the first impression you give others. Read more
Placidus: The most widely used house system in modern Western astrology, which divides houses by time. It distorts at high latitudes, where some charts fall back to whole sign houses.

Q

Quincunx (inconjunct): A minor aspect of 150° between signs that share neither element nor modality. It is read as an awkward fit that asks for ongoing adjustment.

R

Retrograde: A period when a planet appears to move backward through the zodiac as seen from Earth — an optical effect of the orbits. In astrology it is read as a time to review rather than start.
Rising sign: The sign on the eastern horizon at birth, another name for the ascendant's sign. It changes about every two hours, so it needs an accurate birth time. Read more
Ruling planet: The planet associated with a sign: Mars rules Aries, Venus rules Taurus and Libra, and so on. Modern astrology adds Uranus, Neptune and Pluto as co-rulers of Aquarius, Pisces and Scorpio.

S

Saturn return: When Saturn comes back to the place it held at your birth, about every 29.5 years — around ages 29, 59 and 88. It is read as a period of taking stock, responsibility and adult choices.
Sextile: An angle of 60°, usually between signs of compatible elements. A supportive opening that helps most when you act on it.
Sidereal zodiac: The zodiac anchored to the background stars, used in Vedic astrology. Because of the precession of the equinoxes it now sits about 24° behind the tropical zodiac, so many placements shift back a sign.
Solar return: A chart cast for the moment each year when the Sun returns to its exact birth position, near your birthday. Astrologers read it for the themes of the year ahead.
Soul urge number (heart's desire): The sum of the vowels (A, E, I, O, U) in your full birth name, reduced to one digit or a master number. It describes inner motivation — what you want most. Read more
Square: An angle of 90°, between signs of the same modality. It brings friction and pressure that tend to push for change and growth.
Stellium: Three or more planets grouped in one sign or house. It concentrates attention on that sign's style or that house's area of life.
Succedent houses: The 2nd, 5th, 8th and 11th houses, which follow the angular houses. They are linked with resources, stability and what we build up over time.
Sun sign: The zodiac sign the Sun was in at birth — the sign most people mean by "my sign". It describes core identity and drive, and changes roughly monthly. Read more
Synastry: Comparing two birth charts by overlaying them: the aspects between one person's planets and the other's, and which houses each person's planets fall into. Read more

T

Transit: The current position of a planet in the sky, read against a birth chart. Transits are how astrologers describe timing — a transit to your Sun or Moon marks a period when those themes are active.
Trine: An angle of 120°, between signs of the same element. It shows natural ease and talent — sometimes so easy it goes unused.
Tropical zodiac: The zodiac anchored to the seasons: 0° Aries is the March equinox. It is the standard in Western astrology and the one Nuvastro uses.

V

Void-of-course moon: The stretch between the Moon's last major aspect in a sign and its entry into the next sign. It happens every two to three days, and traditionally new starts made then are said to fizzle. Read more

W

Waning moon: The half of the lunar cycle from full moon to new moon, when the lit part shrinks. Moon-calendar tradition favors it for finishing, cutting back, clearing and rest.
Waxing moon: The half of the lunar cycle from new moon to full moon, when the lit part grows each night. Moon-calendar tradition favors it for starting, building and growing.
Whole sign houses: The oldest house system: the whole rising sign is the 1st house, the next sign the 2nd, and so on. It is simple, works at any latitude and is common in traditional astrology.