masc. proper name, Old English Eadmund, literally "prosperity-protector," from ead "wealth, prosperity, happiness" (see Edith). The second element is mund "hand, protection, guardian," from Proto-Germanic *mundō-, from PIE root *man- (2) "hand."
fem. proper name, Old English Eadgyð, from ead "riches, prosperity, good fortune, happiness" + guð "war." A fairly common name; it survived through the Middle Ages, probably on the popularity of St. Eadgyð of Wilton (962-84, abbess, daughter of King Edgar of England), fell from favor 16c., was revived in fashion late 19c. Old English ead (also in eadig "wealthy, prosperous, fortunate, happy, blessed; perfect;" eadnes "inner peace, ease, joy, prosperity") became Middle English edy, eadi "rich, wealthy; costly, expensive; happy, blessed," but was ousted by happy. Late Old English, in its grab-bag of alliterative pairings, had edye men and arme "rich men and poor."
It is the hypothetical source of/evidence for its existence is provided by: Hittite maniiahh- "to distribute, entrust;" Greek mane "hand," Latin manus "hand, strength, power over; armed force; handwriting," mandare "to order, commit to one's charge," literally "to give into one's hand;" Old Norse mund "hand," Old English mund "hand, protection, guardian," German Vormund "guardian;" Old Irish muin "protection, patronage."