Glossary · Astrology
Tithi
तिथि
What does Tithi mean?
A tithi is the time the Moon takes to gain 12 degrees on the Sun, so lunar days are slightly shorter or longer than solar days. Each lunar month has two fortnights: the waxing (shukla paksha) and waning (krishna paksha), each with fifteen tithis.
Tithis anchor the Hindu calendar: Ekadashi fasts, Purnima (full moon) and Amavasya (new moon) observances, and most festivals are set by tithi. In muhurta — electional astrology — the tithi is checked alongside the nakshatra and weekday before beginning anything important.