Two major Islamic festivals are commonly known as Eid: Eid al-Fitr and Eid al-Adha.
Eid al-Fitr occurs at the beginning of Shawwal, immediately after Ramadan. It celebrates the completion of the fasting month and is marked by prayer, charity, family visits, and communal meals. Eid al-Adha begins on 10 Dhu al-Hijjah and is associated with Hajj, sacrifice, and the story of Ibrahim.
Both festivals follow the Islamic lunar calendar, so their dates shift earlier by roughly ten or eleven days each Gregorian year. Local moon-sighting and calendar methods can also cause communities to begin celebrations on different Gregorian dates.
Other Islamic occasions, such as Ashura and Mawlid, are important in various traditions, but they are not generally counted among the two major festivals called Eid. The shared word Eid means a recurring festival or feast.