bars vs gymnastic apparatus

bars and gymnastic apparatus both are nouns.

Word	Noun	Adjective	Verb	Adverb
bars	Yes	No	No	No
gymnastic apparatus	Yes	No	No	No

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

bars: gymnastic apparatus consisting of two parallel wooden rods supported on uprights
gymnastic apparatus: sports equipment used in gymnastic exercises

Other hypernyms of bars include exerciser.

bars (noun)	gymnastic apparatus (noun)
gymnastic apparatus consisting of two parallel wooden rods supported on uprights	sports equipment used in gymnastic exercises