Definition of megistotherm in US English:

megistotherm

noun

Ecology
rare, historical
  • A plant requiring a mean annual temperature of more than 30 degrees C.

Origin

Late 19th century; earliest use found in Nature: a weekly journal of science. From French mégistotherme from ancient Greek μέγιστος + French -therme.

Pronunciation

megistotherm

/mɪˈɡɪstə(ʊ)θəːm/