(1):

(n.) A mounted soldier; a cavalryman.

(2):

(n.) A West Indian fish of the genus Eques, as the light-horseman (E. lanceolatus).

(3):

(n.) A rider on horseback; one skilled in the management of horses; a mounted man.

(4):

(n.) A land crab of the genus Ocypoda, living on the coast of Brazil and the West Indies, noted for running very swiftly.