Cavalry consists of highly mobile military forces, traditionally mounted on animals but nowadays, in those militaries that retain the term "cavalry", on ground or air vehicles.
Classic heavy cavalry was armored and could devastate unprepared opponents by speed and shock. The modern equivalent uses armored fighting vehicles such as tanks, armored infantry fighting vehicles and armored personnel carriers.
Classic light cavalry emphasized mobility, and focused on scouting for the enemy and screening the friendly force. In modern practice, this may be an air assault role, or a role for wheeled vehicles with varying degrees of armor.