uneven bars vs parallel bars

uneven bars and parallel bars both are nouns.

Word	Noun	Adjective	Verb	Adverb
uneven bars	Yes	No	No	No
parallel bars	Yes	No	No	No

As nouns, parallel bars is a hypernym of uneven bars; that is, parallel bars is a word with a broader meaning than uneven bars:

uneven bars: a pair of parallel bars set at different heights; used in women's gymnastics
parallel bars: gymnastic apparatus consisting of two parallel wooden rods supported on uprights

Other hypernyms of uneven bars include bars.

uneven bars (noun)	parallel bars (noun)
a pair of parallel bars set at different heights; used in women's gymnastics	gymnastic apparatus consisting of two parallel wooden rods supported on uprights