Dignities
Domicile
The sign a planet rules, where it is most at home.
Each of the seven traditional planets rules one or two signs. The Sun rules Leo and the Moon Cancer; Mercury rules Gemini and Virgo, Venus Taurus and Libra, Mars Aries and Scorpio, Jupiter Sagittarius and Pisces, and Saturn Capricorn and Aquarius.
A planet in its domicile has the resources to act according to its nature. The ruler of a sign is also the planet that answers for anything placed in that sign.