Cyrillic alphabet vs ABC's

Cyrillic alphabet and ABC's both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cyrillic alphabet	Yes	No	No	No
ABC's	Yes	No	No	No

As nouns, ABC's is a hypernym of Cyrillic alphabet; that is, ABC's is a word with a broader meaning than Cyrillic alphabet:

Cyrillic alphabet: an alphabet derived from the Greek alphabet and used for writing Slavic languages (Russian, Bulgarian, Serbian, Ukrainian, and some other Slavic languages)
ABC's: a character set that includes letters and is used to write a language

Other hypernyms of Cyrillic alphabet include ABC, ABCs, alphabet, bicameral script.

Cyrillic alphabet (noun)	ABC's (noun)
an alphabet derived from the Greek alphabet and used for writing Slavic languages (Russian, Bulgarian, Serbian, Ukrainian, and some other Slavic languages)	a character set that includes letters and is used to write a language