Astrology Glossary
The building blocks of every birth chart, in plain English. Look up an aspect like the trine or square, get to know the four elements and three modalities, or find your decan — the 10° slice of your sign that adds a second flavor to who you are.
Aspects
The angles between planets — how two parts of a chart talk to each other.
Elements
Fire, earth, air, and water — the four temperaments that group the signs.
Modalities
Cardinal, fixed, and mutable — how each sign starts, holds, or releases.
Decans
Each sign split into three 10° thirds, each with its own sub-ruler and flavor.
Aries First DecanMar 21 – Mar 30Aries Second DecanMar 31 – Apr 9Aries Third DecanApr 10 – Apr 19Leo First DecanJul 23 – Aug 1Leo Second DecanAug 2 – Aug 11Leo Third DecanAug 12 – Aug 22Sagittarius First DecanNov 22 – Dec 1Sagittarius Second DecanDec 2 – Dec 11Sagittarius Third DecanDec 12 – Dec 21Taurus First DecanApr 20 – Apr 29Taurus Second DecanApr 30 – May 10Taurus Third DecanMay 11 – May 20Virgo First DecanAug 23 – Sep 1Virgo Second DecanSep 2 – Sep 11Virgo Third DecanSep 12 – Sep 22Capricorn First DecanDec 22 – Dec 31Capricorn Second DecanJan 1 – Jan 10Capricorn Third DecanJan 11 – Jan 19Gemini First DecanMay 21 – May 31Gemini Second DecanJun 1 – Jun 10Gemini Third DecanJun 11 – Jun 20Libra First DecanSep 23 – Oct 2Libra Second DecanOct 3 – Oct 12Libra Third DecanOct 13 – Oct 22Aquarius First DecanJan 20 – Jan 29Aquarius Second DecanJan 30 – Feb 8Aquarius Third DecanFeb 9 – Feb 18Cancer First DecanJun 21 – Jul 1Cancer Second DecanJul 2 – Jul 12Cancer Third DecanJul 13 – Jul 22Scorpio First DecanOct 23 – Nov 1Scorpio Second DecanNov 2 – Nov 11Scorpio Third DecanNov 12 – Nov 21Pisces First DecanFeb 19 – Feb 29Pisces Second DecanMar 1 – Mar 10Pisces Third DecanMar 11 – Mar 20
These terms knit the whole sky together. Read your zodiac sign, explore the planets in the signs, learn the twelve houses, or start from the beginning in our guide to astrology.
