rings vs exerciser

rings and exerciser both are nouns.

Word	Noun	Adjective	Verb	Adverb
rings	Yes	No	No	No
exerciser	Yes	No	No	No

As nouns, exerciser is a hypernym of rings; that is, exerciser is a word with a broader meaning than rings:

rings: gymnastic apparatus consisting of a pair of heavy metal circles (usually covered with leather) suspended by ropes; used for gymnastic exercises
exerciser: sports equipment used in gymnastic exercises

Other hypernyms of rings include gymnastic apparatus.

rings (noun)	exerciser (noun)
gymnastic apparatus consisting of a pair of heavy metal circles (usually covered with leather) suspended by ropes; used for gymnastic exercises	sports equipment used in gymnastic exercises