From an Old English personal name derived from ēad ‘prosperity, riches’ + mund ‘protector’. It was borne by several early royal and saintly figures, including a 9th-century king of East Anglia killed by invading Danes, allegedly for his adherence to Christianity. In the 16th and 17th centuries, there was a good deal of interchange between Edmund and Edward.
Irish: Anglicized form of Gaelic Ó Mongáin ‘descendant of Mongán’, originally a byname for someone with a luxuriant head of hair (from mong ‘hair’, ‘mane’), borne by families from Connacht, County Limerick, and Tyrone. It is also a Huguenot name, traced back to immigrants from Metz.