'antityphoid' originates from the prefix 'anti-' (from Greek 'anti-' meaning 'against') combined with 'typhoid' (from New Latin/English 'typhoid', ultimately from Greek 'typhos' meaning 'smoke, stupor').

'typhoid' entered medical English via New Latin (typhoidēs/typhoides) and French influences in the 18th–19th centuries; the compound 'anti-' + 'typhoid' (as in 'antityphoid serum' or 'antityphoid vaccine') arose in 19th-century medical usage with the development of serums and vaccines.

Initially the parts simply meant 'against typhoid'; over time the compound came to be used both as an adjective meaning 'preventive of typhoid' and as a noun referring specifically to preventive substances (vaccines/sera).