poikilothermism

American  

[poi-kuh-loh-thur-miz-uhm, poi-kil-uh-] / ˌpɔɪ kə loʊˈθɜr mɪz əm, pɔɪˌkɪl ə- /

Or poikilothermy

noun

Zoology.

1. the state or quality of being cold-blooded, as fishes and reptiles.

---

Etymology

Origin of poikilothermism

First recorded in 1900–05; from Greek poikilos “various” + therm- ( def. ) + -ism ( def. )