In chronology, an epoch among the Mohammedans, from which they compute time. The event which gave rise to it was the flight of Mohammed from Mecca; from which the magistrates, fearing his impostures might raise a sedition, expelled him, July 10, adjective D. 622, under the reign of the emperor Heraclius.

The flight of Mohammed from Mecca, September 13, A. D. 622 (subsequently established as the first year of the Moslem era); hence, any flight or exodus regarded as like that of Mohammed.