An Etymological Dictionary of Astronomy and Astrophysics

Of, pertaining to, or caused by heat or temperature.

Etymology (EN): From M.Fr. thermal, from Gk. therme “heat,” cognate with Pers. garm “warm,” as below.

Etymology (PE): Garmâyi, adj. of garmâ “heat, warmth,” from Mid.Pers. garmâg; O.Pers./Av. garəma- “hot, warm;” cf. Skt. gharmah “heat;” cognate with Gk. therme, thermos, as above; PIE *ghworm-/*ghwerm- “warm.”