'barb' originates from Old French, specifically the word 'barbe', ultimately from Latin 'barba' meaning 'beard'.

'barb' changed from Old French 'barbe' (meaning 'beard') into Middle English forms such as 'barbe' or 'barb' and eventually the modern English 'barb', with senses transferred to 'a projecting point'.

Initially it meant 'beard' (a tuft or growth of hair), but over time it evolved to mean 'a projecting pointed part' (like on a hook) and then metaphorically 'a cutting remark'.