folio vs interleaf

folio and interleaf both are nouns.

Word	Noun	Adjective	Verb	Adverb
folio	Yes	No	No	No
interleaf	Yes	No	No	No

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

folio: a sheet of any written or printed material (especially in a manuscript or book)
interleaf: a blank leaf inserted between the leaves of a book

Other hyponyms of folio include flyleaf, page.

folio (noun)	interleaf (noun)
a book (or manuscript) consisting of large sheets of paper folded in the middle to make two leaves or four pages	a blank leaf inserted between the leaves of a book
a sheet of any written or printed material (especially in a manuscript or book)
the system of numbering pages