The Collaborative International Dictionary of English v.0.48:

Equitation \Eq`ui*ta"tion\, n. [L. equitatio, fr. equitare: cf.
   F. ['e]quitation.]
   A riding, or the act of riding, on horseback; horsemanship.
   [1913 Webster]

         The pretender to equitation mounted.     --W. Irving.
   [1913 Webster]

WordNet (r) 3.0 (2006):

equitation
    n 1: the sport of siting on the back of a horse while
         controlling its movements [syn: riding, horseback
         riding, equitation]