Ramadan (; , ; also transliterated
Ramazan,
Ramzan,
Ramadhan, or
Ramathan) is the
ninth month of the
Islamic calendar, and is observed by
Muslims worldwide as a month of
fasting to commemorate the first revelation of the Quran to Muhammad according to Islamic belief. This annual observance is regarded as one of the
Five Pillars of Islam. The month lasts 29–30 days based on the visual sightings of the
crescent moon, according to numerous biographical accounts compiled in the
hadiths.