duet vs duo

duet and duo both are nouns.

Word	Noun	Adjective	Verb	Adverb
duet	Yes	No	No	No
duo	Yes	No	No	No

As nouns, duet and duo are synonyms defined as:

Other synonyms of duet include duette.

As nouns, duet and duo are synonyms defined as:

Other synonyms of duet include couple, twosome.

As nouns, duet and duo are synonyms defined as:

Other synonyms of duet include duette.

As nouns, duet and duo are synonyms defined as:

Other synonyms of duet include brace, couple, couplet, distich, duad, dyad, pair, span, twain, twosome, yoke.

duet (noun)	duo (noun)
(ballet) a dance for two people (usually a ballerina and a danseur noble)	a musical composition for two performers
a musical composition for two performers	a pair who associate with one another
a pair who associate with one another	two performers or singers who perform together
two performers or singers who perform together	two items of the same kind
two items of the same kind