percent vs per centum

percent and per centum both are nouns.

Word	Noun	Adjective	Verb	Adverb
percent	Yes	No	No	No
per centum	Yes	No	No	No

As nouns, percent and per centum are synonyms defined as:

percent and per centum: a proportion in relation to a whole (which is usually the amount per hundred); ten percent

Other synonyms of percent include pct, percentage.

percent (noun)	per centum (noun)
a proportion in relation to a whole (which is usually the amount per hundred); ten percent	a proportion in relation to a whole (which is usually the amount per hundred); ten percent