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
