'antityphoidal' originates from Greek and English elements: the prefix 'anti-' (from Greek 'antí') meaning 'against', combined with 'typhoid' (from modern Latin/English 'typhoid', from Greek 'typhos' meaning 'fever, stupor'), plus the adjectival suffix '-al' (from Latin '-alis') meaning 'pertaining to'.

'anti-' + 'typhoid' (19th century coinage referring to measures against typhoid) combined with the suffix '-al' to form the adjective 'antityphoidal', describing things pertaining to or effective against typhoid.

Initially coined to describe sera, vaccines, or measures 'against typhoid', the term has retained that specific medical/biotic meaning and remains largely unchanged in usage.