'large-billed' originates from Modern English as a compound of 'large' + 'bill'. 'large' ultimately comes from Old French 'large', from Latin 'largus' meaning 'abundant'; 'bill' comes from Old English 'bile' (from Proto-Germanic), meaning 'beak' or 'projecting edge'.

'large-billed' was formed in Modern English by compounding the adjective 'large' and the noun 'bill' (meaning 'beak'), producing a descriptive adjective such as 'large-billed pelican'.

Originally a straightforward compound meaning 'having a large bill', the meaning has remained stable and is still used to describe birds (or sometimes other animals) with notably large bills.