θέρμη
thérmē
“heat”
5 words in English grow from this root.
Diathermy
Medicineδιάdiá
“heating through”
Hyperthermia
Medicineὑπέρhypér
“over-heat”
Hypothermia
Medicineὑπόhypó
“under-heat”
Isotherm
Earthἴσοςísos
“equal heat”
Thermionic
Scienceθέρμηthérmē
“heat-going”