cav·al·ry 
(kăvəl-rē)
(kăvəl-rē)n. pl. cav·al·ries
1. A highly mobile army unit using vehicular transport, such as light armor and helicopters.
2. Troops trained to fight on horseback.
[French cavalerie, from Italian cavalleria, from cavaliere, cavalier, from Old Italian; see CAVALIER.]
caval·ry·man n.