'abomasum' originates from New Latin, specifically the word 'abomasus', where 'ab-' meant 'away from' and 'omasus' referred to 'the third stomach of a ruminant'.

'abomasus' transformed into the modern English word 'abomasum', and its plural form became 'abomasa'.

Initially, it referred specifically to the fourth stomach of ruminants, and this meaning has remained consistent in modern usage.