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Rabiý al-Thani (, also known as Rabi' al-Akhirah (), Rabi al-Akhir (), or Rabi' II is the fourth month of the Islamic calendar. The name Rabë' al-Thani means "the second spring" in Arabic, referring to its position in the pre-Islamic Arabian calendar.
The word "Rabi" means "spring" and Al-thani means "the second" in the Arabic language, so "Rabi' al-Thani" means "the second spring" in Arabic. As the Islamic calendar is a purely lunar calendar, the month naturally rotates over solar years, so Rabëý al-Thani can fall in spring or any other season. Therefore, the month cannot be related to the actual season of spring.
The Islamic calendar is a purely lunar calendar, and months begin when the first crescent of a new moon is sighted. Since the Islamic lunar year is 11 to 12 days shorter than the tropical year, Rabë' al-ThÃÂnë migrates throughout the seasons. The estimated start and end dates for Rabë' al-ThÃÂnë are as follows (based on the Umm al-Qura calendar of Saudi Arabia):