Old English mihte, meahte, originally the past tense of may (Old English magen "to be able"), thus "*may-ed." The noun might-have-been "something that might have happened but did not," also "someone that might have been greater but wasn't," is by 1848.
"quality of being able, ability to do or act, power," Middle English might, from Old English miht, earlier mæht "bodily strength, power; authority, dominion, control; ability," from Proto-Germanic *makhti- (source also of Old Norse mattr, Old Frisian, Middle Dutch, Dutch macht, Old High German maht, German Macht, Gothic mahts), a Germanic suffixed form of the PIE root *magh- "to be able, have power."
"possessed of or endowed with might; having much ability, strength, or power," Old English mihtig, earlier mæhtig, from Proto-Germanic *mahtiga- (source also of Old Frisian mechtig, Old Saxon mahtig, Dutch machtig, German mächtig), from the source of might (n.). As an adverb, "very, exceedingly, greatly," it is attested from c. 1300, though such use now is considered colloquial.
Proto-Indo-European root meaning "to be able, have power." It forms all or part of: dismay; deus ex machina; may (v.1) "am able;" might (n.) "bodily strength, power;" main; machine; mechanic; mechanism; mechano-; mage; magi; magic.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit mahan "great;" Greek mēkhanē "device, means," mekhos, makhos "means, instrument;" Old Church Slavonic mošti, Russian moč' "can, be able;" Old English mæg "I can," Gothic mag "can, is able," Old High German magan, Old Norse magn "power, might."
fem. proper name, from French Mathilde, which is of Germanic origin, literally "mighty in battle;" compare Old High German Mahthilda, from mahti "might, power" (see might (n.)) + hildi "battle," from Proto-Germanic *hildiz "battle" (see Hilda). Matilda (1102-1167), daughter of Henry I, claimant to the throne during the Anarchy, usually is not reckoned among the kings and queens of England.
The name also was late 19c. Australian slang for "a traveler's bundle or swag," hence the expression waltzing Matilda "to travel on foot" (by 1889).
In my electorate nearly every man you meet who is not "waltzing Matilda" rides a bicycle. ["Parliamentary Debates," Australia, 1907]
The lyrics of the song of that name, sometimes called the unofficial Australian national anthem, are said to date to 1893.
mid-15c., agent noun from lend (v.). Old English had laenere, agent noun from lænan; the Middle English word might be a new formation or it might be the older word with an unetymological -d- from lend.
masc. proper name, from Old French Raimund, from Frankish *Raginmund "counsel-protection" or "might-protection," from ragin "counsel, might" + mund "hand, protection," from Proto-Germanic *mundō(source also of Old High German munt, Old English mund, and the second element in Edmund, Sigismund, etc.), from PIE root *man- (2) "hand."
early 15c., puissaunce, "power, strength, authority," from Old French puissance, poissance "power, might" (12c.), from puissant (see puissant).