manual alphabet vs ABC's

manual alphabet and ABC's both are nouns.

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

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

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

Other hypernyms of manual alphabet include ABC, ABCs, alphabet.

manual alphabet (noun)	ABC's (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