rondeau vs poem

rondeau and poem both are nouns.

Word	Noun	Adjective	Verb	Adverb
rondeau	Yes	No	No	No
poem	Yes	No	No	No

As nouns, poem is a hypernym of rondeau; that is, poem is a word with a broader meaning than rondeau:

rondeau: a French verse form of 10 or 13 lines running on two rhymes; the opening phrase is repeated as the refrain of the second and third stanzas
poem: a composition written in metrical feet forming rhythmical lines

Other hypernyms of rondeau include verse form.

rondeau (noun)	poem (noun)
a French verse form of 10 or 13 lines running on two rhymes; the opening phrase is repeated as the refrain of the second and third stanzas	a composition written in metrical feet forming rhythmical lines
a musical form that is often the last movement of a sonata