robin, n.
1 (also robin redbreast) a small brown European bird, Erithacus rubecula, the adult of which has a red throat and breast.
2 US a red-breasted thrush, Turdus migratorius.
3 a bird similar in appearance etc. to either of these.
Robin Hood (with ref. to the legend of the medieval forest outlaw) a person who acts illegally or unfavourably towards the rich for the benefit of the poor.
ME f. OF, familiar var. of the name Robert