Pronunciation: (dOO'ō, dyOO'ō),[key] —n., —pl.du•os. 1. Music.duet.
2. two persons commonly associated with each other; couple.
3. two animals or objects of the same sort; two things ordinarily placed or found together; a pair: a duo of lovebirds.
a combining form meaning “two,” used in the formation of compound words: duologue.