percentage sign vs percent sign

percentage sign and percent sign both are nouns.

Word	Noun	Adjective	Verb	Adverb
percentage sign	Yes	No	No	No
percent sign	Yes	No	No	No

As nouns, percentage sign and percent sign are synonyms defined as:

percentage sign and percent sign: a sign (`%') used to indicate that the number preceding it should be understood as a proportion multiplied by 100

percentage sign (noun)	percent sign (noun)
a sign (`%') used to indicate that the number preceding it should be understood as a proportion multiplied by 100	a sign (`%') used to indicate that the number preceding it should be understood as a proportion multiplied by 100