manual alphabet vs alphabet

manual alphabet and alphabet both are nouns.

Word	Noun	Adjective	Verb	Adverb
manual alphabet	Yes	No	No	No
alphabet	Yes	No	No	No

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

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

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

manual alphabet (noun)	alphabet (noun)
an alphabet used by the deaf; letters are represented by finger positions	the elementary stages of any subject (usually plural)
	a character set that includes letters and is used to write a language