An Etymological Dictionary of Astronomy and Astrophysics

Relating to or describing any process in which a system releases heat to its surrounding environment.

Etymology (EN): From → exo- + -therm, from Gk. therme “heat,” from PIE *ghwerm-/*ghworm- “warm;” cf. Pers. garm “warm;” L. fornax “an oven;” O.E. wearm “warm” + → -ic.

Etymology (PE): From garmâ “heat, warmth” (Mid.Pers. garm; O.Pers./Av. garəma- “hot, warm;” cf. Skt. gharmah “heat;” Gk. thermos “warm;” L. formus “warm;” P.Gmc. *warmaz; O.E. wearm; O.H.G., Ger. warm; PIE *ghworm-/*ghwerm-, as above) + zâ verbal adj. and agent noun of zâdan “to bring foth, give birth,” (Mid.Pers. zâtan; Av. zan- “to bear, give birth to a child, be born,” infinitive zazâite, zâta- “born;” cf. Skt. janati “begets, bears;” L. gignere “to beget;” PIE base *gen- “to give birth, beget”).