Learn Astrology
The Glossary
Plain-language definitions for the terms used across this site -- aspects, chart basics, and the mechanics behind every horoscope.
Aspects
Aspect
The angular distance between two points in the sky (or two charts), measured in degrees along the zodiac -- the basis for reading how two planets interact.
Conjunction
Two points sitting at (or very near) the same degree of the zodiac -- 0° apart, the tightest possible aspect.
Opposition
Two points 180° apart on the zodiac -- directly across from each other, the widest possible separation.
Orb
The margin of degrees on either side of an exact aspect angle that still counts as that aspect being active.
Sextile
Two points 60° apart on the zodiac -- a supportive, low-friction angle.
Square
Two points 90° apart on the zodiac -- a tension aspect, traditionally read as friction that pushes action.
Trine
Two points 120° apart on the zodiac -- the aspect considered the most naturally harmonious, since points at this distance always share an element.
Chart Basics
House
One of twelve divisions of the sky, fixed relative to your birth location, that a natal chart maps planets into.
Moon Sign
The zodiac sign the Moon was passing through at the moment of your birth.
Natal Chart
A map of exactly where every planet was, from the perspective of your birth location, at the moment you were born.
Rising Sign (Ascendant)
The zodiac sign that was coming up over the eastern horizon at your exact time and place of birth.
Ruling Planet
The planet traditionally associated with a zodiac sign, whose movements are read as especially relevant to that sign.
Sun Sign
The zodiac sign the Sun was in on your date of birth -- the sign nearly everyone means when they ask "what's your sign?"
Cycles
Moon Phase
A measurement of the angle between the Sun and Moon, which determines how much of the Moon's lit half is visible from Earth.
Retrograde
The optical illusion of a planet appearing to move backward through the zodiac from Earth's point of view.
Synodic Month
The roughly 29.5-day cycle from one New Moon to the next -- the basis for the Moon phase cycle.
Transit
Where a planet is positioned right now, as opposed to where it was at a specific past moment like your birth.
Void-of-Course
A period when the Moon has made its last major aspect before leaving its current sign, and won't make another until it enters the next one.
Waxing & Waning
Waxing means the Moon's illuminated portion is growing toward full; waning means it's shrinking back toward new.
Structure
Degree
A unit of position along the zodiac wheel -- 0° to 360° for the full circle, or 0° to 30° within a single sign.
Ecliptic
The apparent path the Sun traces across the sky over a year, as seen from Earth -- the backbone the entire zodiac is measured against.
Element
One of four groupings -- Fire, Earth, Air, Water -- that every zodiac sign belongs to, three signs each.
Modality
One of three groupings -- Cardinal, Fixed, Mutable -- describing a sign's role within its season: starting it, sustaining it, or closing it out.
Zodiac Wheel
The full 360° circle of the ecliptic, divided into twelve equal 30° segments -- the twelve zodiac signs.