1649, "small number of military men detailed for some purpose," from Fr. esquade,
from M.Fr. escadre,
from Sp. escuadra
or It. squadra
"battalion," lit. "square," from V.L. *exquadra
). Until the introduction of automatic weapons, infantry troops tended to fight in a square formation to repel cavalry or superior forces. Sports sense is recorded from 1902.