An Etymological Dictionary of Astronomy and Astrophysics

Process during which heat is absorbed by the system from outside.

Etymology (EN): → endo- + -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) + gir present tense stem of gereftan “to take, seize, catch” (Mid.Pers. griftan, Av./O.Pers. grab- “to take, seize,” cf.
Skt. grah-, grabh- “to seize, take,” graha “seizing, holding, perceiving,” M.L.G. grabben “to grab,” from P.Gmc. *grab, E. grab “to take or grasp suddenly;” PIE base *ghrebh- “to seize”).