2. Retaliate on behalf of somebody: To retaliate on behalf of yourself or somebody else for a wrong done.
Pretty simmular to revenge. The DIFFERENCE, however is, that revenge is to get even with someone for something he did to you. Avenge is to get even with someone for something he did to someone you care about.
2. She was determined to avenge her brother.
Here follows the definition of the words avenge and revenge + the difference between avenge and revenge.
Both words are about repaying a wrong. The differences between them have to do with grammar and shades of meaning, though there is considerable overlap in meaning, dictated by usage over time. Grammatically speaking, avenge is a verb only; revenge is a verb and more usually a noun. Avenge traditionally relates not only to repaying a wrong but to getting justice on somebody else's behalf as a remedy for that wrong. Revenge traditionally relates to getting even with an adversary by inflicting punishment or harm.
Though both avengeand revenge can be used as transitive verbs with reflexive pronouns, revenge is commoner in this use: The dictatorship avenged itself on the partisans' radio station by burning it to the ground; As a victim of a hate crime, she finally avenged herself on the perpetrators.
They vowed to avenge their sister's murder (or their murdered sister).
In an act of revenge for the bombing of our ship, our navy shelled the terrorists' training camps; Bands of irregular soldiers set out to revenge their leader's assassination.