Attested in English since 1545, from French troupe (back-formation of troupeau, diminutive of Medieval Latin troppus "flock") and Middle French trouppe (from Old French trope (“band, company, troop”)), both of Germanic origin from Old Frankish *þrop (throp, “assembly, gathering”), from Proto-Germanic *þurpą (“village, land, estate”), from Proto-Germanic *treb- (“dwelling, settlement”). Akin to Old English þorp, þrop (“village, farm, estate”) (Modern English thorp), Old Frisian þorp, Old Norse þorp. More at thorp.
troop (plural troops)
- A collection of people; a company; a number; a multitude.
- (military) A small unit of cavalry or armour commanded by a captain, corresponding to a platoon or company of infantry.
- A detachment of soldiers or police, especially horse artillery, armour, or state troopers.
- Soldiers, military forces (usually "troops").
- (nonstandard) A company of stageplayers; a troupe.
- A particular roll of the drum; a quick march.
- A unit of girl or boy scouts.
- (Can we verify(+) this sense?) An orderly crowd.
- (mycology) Mushrooms that are in a close group but not close enough to be called a cluster.
- To move in numbers; to come or gather in crowds or troops.
- To march on; to go forward in haste.
- to move or march as if in a crowd; “The children trooped into the room”.
- troop the colour (British, military)
- “troop” in the Canadian Oxford Dictionary, Second Edition, Oxford University Press, 2004.
- “troop” in Douglas Harper, Online Etymology Dictionary (2001).