"CAVALRY: an army component moving in motor vehicles or helicopters and assigned to combat missions that require great mobility (Merriam-Webster)"
Err... yes, but... that's a metaphorical usage.
Cavalry is literally soldiers who fight on horseback. As modern warfare replaced horses, 'cavalry' got used to refer to battlefield systems which performed similar roles. (ie, metaphorical cavalry).
(Genshin, where are your horses?)
