All 3 Uses

avenge
in
The Apology, by Plato
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Whereas, upon your view, the heroes who fell at Troy were not good for much, and the son of Thetis above all, who altogether despised danger in comparison with disgrace; and when he was so eager to slay Hector, his goddess mother said to him, that if he avenged his companion Patroclus, and slew Hector, he would die himself—'Fate,' she said, in these or the like words, 'waits for you next after Hector;' he, receiving this warning, utterly despised danger and death, and instead of fearing them, feared rather to live in dishonour, and not to avenge his friend.†

avenged = took revenge
Whereas, upon your view, the heroes who fell at Troy were not good for much, and the son of Thetis above all, who altogether despised danger in comparison with disgrace; and when he was so eager to slay Hector, his goddess mother said to him, that if he avenged his companion Patroclus, and slew Hector, he would die himself—'Fate,' she said, in these or the like words, 'waits for you next after Hector;' he, receiving this warning, utterly despised danger and death, and instead of fearing them, feared rather to live in dishonour, and not to avenge his friend.†

avenge = take revenge for
Let me die forthwith,' he replies, 'and be avenged of my enemy, rather than abide here by the beaked ships, a laughing-stock and a burden of the earth.†
*

avenged = took revenge

Definitions:

(1) (avenge)
take revenge for a perceived wrong
(2) (meaning too rare to warrant focus)
Avengers is also used as a proper noun to refer to fictious superheroes or naval ship names. Avenger has also been used to describe classes of weaponry.