'anal-oral' is a modern English compound formed from the combining forms 'anal' and 'oral'. 'Anal' originates from Latin, specifically the word 'anus', where 'anus' meant 'ring' or 'the opening at the end of the alimentary canal' and developed into English 'anal' meaning 'relating to the anus'. 'Oral' originates from Latin, specifically the word 'oralis' (from 'os, oris'), where 'os/oris' meant 'mouth' and developed into English 'oral' meaning 'relating to the mouth'.

'anal' entered English via Late Latin and Medieval Latin from Latin 'anus' and became the adjective 'anal' in modern English; 'oral' came from Latin 'oralis' (from 'os, oris') through Old French/Latin influences into Middle English and then modern English. The hyphenated compound 'anal-oral' is a relatively recent formation in technical and medical usage, combining the two established adjectives.

Initially, the separate roots meant 'relating to the anus' and 'relating to the mouth'; over time, combining them produced the compound meaning 'relating to both the anus and the mouth', often with specific reference to contact or routes of transmission between the two.