'neurotoxin' originates from Greek combining form 'neuro-' (from Greek 'neûron', meaning 'nerve') and 'toxin' (from Greek 'toxikon', meaning 'poison'), formed in modern scientific English.

'neûron' entered scientific vocabulary as the combining form 'neuro-' via New Latin/Modern scientific coinage; 'toxikon' passed into Late Latin as 'toxicum' and into English as 'toxin' in the 19th century; these elements were combined in English to form 'neurotoxin' in the 20th century.

Initially the elements meant 'nerve' and 'poison' respectively; together in modern usage they specifically denote 'a substance that damages the nervous system' rather than any general poison.