folio vs piece of paper

folio and piece of paper both are nouns.

Word	Noun	Adjective	Verb	Adverb
folio	Yes	No	No	No
piece of paper	Yes	No	No	No

As nouns, piece of paper is a hypernym of folio; that is, piece of paper is a word with a broader meaning than folio:

folio: a sheet of any written or printed material (especially in a manuscript or book)
piece of paper: paper used for writing or printing

Other hypernyms of folio include sheet, sheet of paper.

folio (noun)	piece of paper (noun)
a book (or manuscript) consisting of large sheets of paper folded in the middle to make two leaves or four pages	paper used for writing or printing
a sheet of any written or printed material (especially in a manuscript or book)
the system of numbering pages