calor

Calor, caloris is third declension masculine, formed from caleo, "to be warm", with the -or suffix that Latin uses for abstract states: dolor, timor, amor, calor. All of them are masculine, and all of them name the condition rather than the thing in it. So calor is heat as such, not a hot object.

The transferred sense, the heat of anger or of love, is as ordinary in Latin as in English and needs no signalling. Distinguish aestus, which is the oppressive heat of high summer or the surge of the tide, and ardor, which burns. The adjective is calidus, syncopated to caldus in speech, and that is what reached Italian caldo and Spanish caliente. English gets cauldron, chowder and, oddly, nonchalant from the same root; calorie is a nineteenth-century coinage on the Latin stem rather than a Roman word.