The Collaborative International Dictionary of English v.0.48:

homoiotherm \homoiotherm\ n. (Biol.)
   A homoiothermal animal.

   Syn: homeotherm.
        [PJC] Homoiothermal

WordNet (r) 3.0 (2006):

homoiotherm
    n 1: an animal that has a body temperature that is relatively
         constant and independent of the environmental temperature
         [syn: homeotherm, homoiotherm, homotherm]