1. Islamic calendar - Noun
2. Islamic calendar - Proper noun
the lunar calendar used by Muslims; dates from 622 AD (the year of the Hegira); the beginning of the Muslim year retrogresses through the solar year completing the cycle every 32 years
Source: WordNetIslamic calendars The tabular Islamic calendar usually has 12 lunar months that alternate between 30 and 29 days every year, but an intercalary day is added to the last month of the year 11 times within a 30-year cycle. Source: Internet
For example, the Islamic calendar dates not from the date of the Hegira (16 May AD 622) but from the following new year (16 July AD 622). Source: Internet
The first month of the Islamic calendar, Muharram is a mourning period in remembrance of Imam Husain-Prophet Muhammad's grandson and his family and companions who were martyred by Yazid in Karbala (Iraq) in 680 AD. Source: Internet
Eid al-Fitr or the “Feast of Breaking the Fast” in English, comes on the first day of Shawwal, the tenth month of the Islamic calendar, signaling the end of Ramadan. Source: Internet
Since the Islamic calendar is a lunar calendar, Ramadan begins with the sighting of the new crescent moon which is why it could begin either on the 26th or the 27th of this month. Source: Internet
Astronomical considerations The Islamic calendar is not to be confused with a lunar calendar that is based on astronomical calculations. Source: Internet