Reply #3: brief eymology of "troops"

[expatriot]

1545, "body of soldiers," from M.Fr. troupe, from O.Fr. trope "band of people, company, troop" (13c.), probably from Frank. *throp "assembly, gathering of people" (cf. O.E. ðorp, O.N. thorp "village," see thorp). OED derives the O.Fr. word from L. troppus "flock," which is of unknown origin but may be from the Gmc. source. The verb is attested from 1565, "to assemble;" meaning "to march" is recorded from 1592; that of "to go in great numbers, to flock" is from 1610. Trooper "soldier in the cavalry" is first attested 1640; extended to "mounted policeman" (1858, in Australian) then to "state policeman" (U.S.) by 1911.