platoon
n.
1630s, from French peloton "platoon, group of people," from Middle French peloton (15c.), literally "little ball," hence, "agglomeration," diminutive of Old French pelote "ball" (see pellet).
v.
in baseball, "to alternate (a player) with another in the same position," 1967, from platoon, n., which had been used in team sports since 1941.