etude vs opus

etude and opus both are nouns.

Word	Noun	Adjective	Verb	Adverb
etude	Yes	No	No	No
opus	Yes	No	No	No

As nouns, opus is a hypernym of etude; that is, opus is a word with a broader meaning than etude:

etude: a short composition for a solo instrument; intended as an exercise or to demonstrate technical virtuosity
opus: a musical work that has been created

Other hypernyms of etude include composition, musical composition, piece, piece of music.

etude (noun)	opus (noun)
a short composition for a solo instrument; intended as an exercise or to demonstrate technical virtuosity	a musical work that has been created