signature vs autograph

signature and autograph both are nouns.

Word	Noun	Adjective	Verb	Adverb
signature	Yes	No	No	No
autograph	Yes	No	Yes	No

As nouns, autograph is a hyponym of signature; that is, autograph is a word with a more specific, narrower meaning than signature:

signature (noun)	autograph (noun)
a distinguishing style	something written by one's own hand
your name written in your own handwriting	a person's own signature
a sheet with several pages printed on it; it folds to page size and is bound with other signatures to form a book
the sharps or flats that follow the clef and indicate the key
a melody used to identify a performer or a dance band or radio/tv program

signature (verb)	autograph (verb)
	mark with one's signature