From Latin 'caldaria' (hot-water pot), from 'calidus' (warm), from PIE *kelh1- (warm).
A large metal pot with a handle, used for cooking over an open fire; figuratively, a situation characterized by turbulence or strong emotions.
From Anglo-Norman 'caudron' and Old French 'chaudron,' augmentative of 'chaudiere' (a cooking pot), from Late Latin 'caldāria' (a pot for hot water), from Latin 'caldārius' (pertaining to warming), from 'calidus' (warm, hot). Latin 'calidus' derives from 'calēre' (to be warm, to glow), from Proto-Indo-European *kelh₁- (warm, hot). The 'l' in the English spelling was reintroduced in the sixteenth century by association with the Latin root. Key roots
The word 'nonchalant' is a distant relative of 'cauldron.' French 'nonchalant' comes from 'non' (not) + 'chaloir' (to care, to be warm about), from Latin 'calēre' (to be warm). To be nonchalant is literally to 'not be hot' — to lack the warmth of caring — making it the emotional opposite of a cauldron.