Source : Webster's Revised Unabridged Dictionary (1913)

Equitant \Eq"ui*tant\, a. [L. equitans, -antis, p. pr. of
   equitare to ride, fr. eques horseman, fr. equus horse.]
   1. Mounted on, or sitting upon, a horse; riding on horseback.

   2. (Bot.) Overlapping each other; -- said of leaves whose
      bases are folded so as to overlap and bestride the leaves
      within or above them, as in the iris.