I. ˈfō-lē-ˌō noun
( plural fo·li·os )
Etymology: Middle English, from Latin, ablative of folium
Date: 15th century
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
II. transitive verb
Date: 1858
: to put a serial number on each leaf or page of