'allantoic-bearing' originates from English, specifically from the adjective 'allantoic' + the present participle 'bearing'; 'allantoic' ultimately comes from Greek 'allantois', where the root 'allant(o)-' meant 'sausage-shaped' (used for a sac-like structure), and 'bearing' comes from Old English 'beran' meaning 'to carry'.

'allantoic' came into English via New Latin/Modern scientific usage from Greek 'allantois' (ἀλλαντοΐς) and Medieval/Modern Latin forms; 'bearing' developed from Old English 'beran' (to carry) through Middle English into the modern English participle 'bearing', and the compound usage 'allantoic-bearing' is a modern scientific formation combining them.

Initially, elements referred to a 'sausage-shaped' sac (Greek 'allantois') and 'to carry' (Old English 'beran'); combined in modern scientific English they mean 'carrying or having an allantois', a meaning that remains descriptive in embryology.