Moat
late Middle English: from Old French mote ‘mound’.
wiktionary
From Middle English mote, from Old French mote(“mound, embankment”); compare also Old French motte(“hillock, lump, clod, turf”), from Medieval Latin mota(“a mound, hill”), of Germanic origin, perhaps via Frankish *mot, *motta(“mud, peat, bog, turf”), from Proto-Germanic *mutô, *mudraz, *muþraz(“dirt, filth, mud, swamp”), from Proto-Indo-European *(s)mut-(“dark, dirty”). Cognate with Alemannic German Mott, Mutte(“peat, turf”), Bavarian Mott(“peat, turf”), dialectal Dutch mot(“dust, fine sand”), Saterland Frisian mut(“grit, litter, humus”), Swedish muta(“to drizzle”), Old English mot(“speck, particle”). More at mote, mud, smut.
As term for a business strategy popularized by American investor Warren Buffett.
etymonline
moat (n.)
c. 1300, mote "a mound, a hill" (a sense now obsolete); late 14c., "ditch or deep trench dug round the rampart of a castle or other fortified place," from Old French mote "mound, hillock, embankment; castle built on a hill" (12c.; Modern French motte) and directly from Medieval Latin mota "mound, fortified height," a word of unknown origin, perhaps from Gaulish mutt, mutta.
The sense shifted in Norman French from the castle mound to the ditch dug around it. For a similar evolution, compare ditch (n.) and dike. As a verb, "to surround with a moat," early 15c. Related: Moated.
