'tetanus' originates from New Latin/Latin, specifically the word 'tetanus', ultimately from Greek 'tetanos' where the root (from 'teínein') meant 'to stretch' or 'to strain'.

'tetanus' changed from the Greek word 'tetanos' (τετάνος) meaning 'spasm, convulsion', was adopted into Latin/New Latin as 'tetanus', and entered English with its medical sense through Late Latin/Modern medical usage.

Initially, it referred to a 'stretching' or 'spasm' (Greek sense), and over time it came to denote the specific infectious disease characterized by sustained muscle contractions (modern medical sense).