Origin and history of warm

Old English wearm, "having a moderate degree of heat," from Proto-Germanic *warmaz (source also of Old Saxon, Old Frisian, Middle Dutch, Old High German, German warm, Old Norse varmr, Gothic warmjan "to warm").

A word of uncertain origin. On one guess it is from PIE root *gwher- (source of Greek thermos "warm;" Latin formus "warm," Old English bærnan "to kindle"). On another it is connected to the source of Old Church Slavonic goriti "to burn," varŭ "heat," variti "to cook, boil;" and Lithuanian vérdu, virti "to seethe."

The use of distinct words, based on degree of heat, for warm and hot is general in Balto-Slavic and Germanic, but in other languages one word often covers both (Greek thermos; Latin calidus, French chaud, Spanish caliente).

In reference to feelings, etc., "ardent, full of zeal," it is attested from late 15c. Of colors from 1764. The sense in guessing games of "close to the thing that is sought" is recorded by 1860, probably from earlier use in hunting in reference to the scent or trail (1713).

Warm-blooded in reference to mammals is recorded from 1793. Warm-hearted, "of a generous and affectionate nature, inclined to seek friendship," is by c. 1500.

Middle English warmen, from Old English wyrman "make warm" and wearmian "become warm;" from the root of warm (adj.). Related: Warmed; warming.

Warming-pan, "large, covered, long-handled pan full of live coals, for warming beds," is by 1570s.