Source : Webster's Revised Unabridged Dictionary (1913)

Enema \En"e*ma\, n.; pl. L. {Enemata}. [L. enema, Gr. ?, fr. ?
   to send in; ? in + ? to send.] (Med.)
   An injection, or clyster, thrown into the rectum as a
   medicine, or to impart nourishment. --Hoblyn.

Source : WordNet®

enema
     n : injection of a liquid through the anus to stimulate
         evacuation; sometimes used for diagnostic purposes [syn:
         {clyster}]
     [also: {enemata} (pl)]