Emily Dickinson Lexicon

HE-GI'RA, n. [Ar. from هَجَرَ hajara, to remove, to desert.]

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 16, A. D. 622, under the reign of the emperor Heraclius. Harris. Encyc.