'avenge' originates from Old French, specifically the word 'avengier', ultimately related to Latin 'vindicare' where the root meant 'to claim, to punish'.

'avenge' changed from Old French 'avengier' into Middle English forms such as 'avengen' and eventually became the modern English word 'avenge'.

Initially it carried senses related to 'vindicate' or 'claim on behalf of' and over time the meaning shifted toward 'to take vengeance or inflict punishment in return for a wrong'.