Islamic calendar
The Hijri calendar (Arabic: ٱلتَّقْوِيم ٱلْهِجْرِيّ, romanized: al-taqwīm al-hijrī), also known in English as the Islamic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 or 355 days. It is used to determine the dates of Islamic holidays and rituals, such as the annual fasting and the annual season for the great pilgrimage.