'bacterioprecipitin' originates from Neo-Latin/Modern Latin, combining the prefix 'bacterio-' (from Greek 'bakterion') and 'precipitin' (formed from 'precipitate' + the protein suffix '-in'), where 'bakterion' meant 'little rod' and '-in' indicated a protein.

'bacterioprecipitin' was formed in scientific usage in the 20th century by attaching the prefix 'bacterio-' (from Greek 'bakterion') to the late-19th-century coinage 'precipitin' (a term for proteins that cause precipitation), producing the compound now used in immunology.

Initially, 'precipitin' referred broadly to proteins causing precipitation; over time the compound 'bacterioprecipitin' came to denote specifically an antibody that precipitates bacterial antigens in serological testing.