1390, "government, rule, control," from O.Fr. regiment "government, rule" (1314), from L.L. regimentum "rule, direction," from L. regimen (see regimen). Meaning "unit of an army" first recorded 1579 (originally the reference was to permanent organization and discipline), from French. The verb, with sense of "to form into a regiment" is first recorded 1617. Regimentation first recorded 1877. Regimentals "dress proper to a particular regiment, militaty uniform" is attested from 1742.