Source : Webster's Revised Unabridged Dictionary (1913)

Cavalryman \Cav"al*ry*man\, n.; pl. {Cavalrymen}.
   One of a body of cavalry.

Source : WordNet®

cavalryman
     n 1: a soldier in a motorized army unit [syn: {trooper}]
     2: a soldier mounted on horseback; "a cavalryman always takes
        good care of his mount" [syn: {trooper}]