'antrum' originates from Latin, specifically the word 'antrum', ultimately from Greek 'antron' where it meant 'cave'.

'antrum' comes into English via Latin from Greek 'antron' (ἄντρον); the Greek term meant 'cave' and passed into Latin as 'antrum', later used in English with anatomical sense (plural 'antra').

Initially it meant 'cave' in Greek and Latin; over time the word took on a more specialized anatomical sense meaning 'a cavity or hollow (in the body)', which is its primary modern usage.