'antitetanus' originates from Greek elements 'anti-' and 'tetanos', where 'anti-' meant 'against' and 'tetanos' (from Greek 'tétanos') referred to 'tension' or the condition produced by severe muscle contraction.

'antitetanus' was formed in New Latin/medical Latin from the prefix 'anti-' + 'tetanus' (itself from Greek 'tétanos'), and the compound entered modern English usage in medical contexts as 'antitetanus'.

Initially it simply meant 'against tetanus' (i.e., opposing the disease), and over time it has retained that specific medical meaning of an agent or property that prevents or treats tetanus.