'anti-precipitin' originates from the Greek prefix 'anti-' (meaning 'against') combined with 'precipitin', which itself was formed in English by combining 'precipitate' (from Latin) with the protein-forming suffix '-in'.

'precipitin' was coined in modern scientific English by deriving 'precipitate' (from Latin 'praecipitare', 'to throw or fall headlong') and adding the English chemical/protein suffix '-in'; 'anti-precipitin' was later formed by prefixing 'anti-' to denote action against a precipitin.

Originally related to the process of precipitation ('to fall down' or 'throw down'), the term 'precipitin' came to mean an antibody causing precipitation in immunology; 'anti-precipitin' later came to mean an antibody acting against such precipitins or against the precipitation reaction.