Definition of folio
plural folios
1 a
:a leaf especially of a manuscript or book
b
:a leaf number
c
:a page number
d
:an identifying reference in accounting used in posting
2 a
:a sheet of paper folded once
b
:a case or folder for loose papers
3 a
:the size of a piece of paper cut two from a sheet;
also
:paper or a page of this size
b
:a book printed on folio pages
c
:a book of the largest size
4
:a certain number of words taken as a unit or division in a document for purposes of measurement or reference
