Source : Webster's Revised Unabridged Dictionary (1913)

Poikilothermous \Poi`ki*lo*ther"mous\ (-m[u^]s), a. (Physiol.)
   Poikilothermal.

Source : WordNet®

poikilothermous
     adj : of animals except birds and mammals; having body temperature
           that varies with the environment [syn: {poikilothermic},
            {heterothermic}, {ectothermic}]