'animal-headed' is a compound of the noun 'animal' and the adjective-forming element from 'head' (past participle 'headed'). 'animal' originates from Latin, specifically the word 'animalis,' where 'anima' meant 'breath' or 'soul'. 'head' originates from Old English 'heafod'.

'animal' passed into Middle English from Latin via Old French and remained as 'animal'; 'head' came from Old English 'heafod' to Middle English 'hede' and modern English 'head', with the adjectival form 'headed' formed by adding the past participle/adjectival suffix. The compound 'animal-headed' is a straightforward modern English compound formed from these elements.

Initially the components referred to 'animal' (a living creature) and 'head' (the upper part of the body); combined, they have long meant 'having the head of an animal' and this basic sense has been stable in modern usage.