finger alphabet vs ABCs

finger alphabet and ABCs both are nouns.

Word	Noun	Adjective	Verb	Adverb
finger alphabet	Yes	No	No	No
ABCs	Yes	No	No	No

As nouns, ABCs is a hypernym of finger alphabet; that is, ABCs is a word with a broader meaning than finger alphabet:

finger alphabet: an alphabet used by the deaf; letters are represented by finger positions
ABCs: a character set that includes letters and is used to write a language

Other hypernyms of finger alphabet include ABC's, ABC, alphabet.

finger alphabet (noun)	ABCs (noun)
an alphabet used by the deaf; letters are represented by finger positions	a character set that includes letters and is used to write a language