folio

UK: /ˈfəʊlɪəʊ/ US: /ˈfoʊliˌoʊ/ ,(fō′lē ō′)

Inflections of 'folio' (n): npl: folios

Inflections of 'folio' (v): (⇒ conjugate)

folios

v 3rd person singular

folioing

v pres p

folioed

v past

folioed

v past p

WordReference Random House Learner's Dictionary of American English © 2026

fo•li•o /ˈfoʊliˌoʊ/   n. [countable] , pl. -li•os.

1. Printing a sheet of paper folded once to make two leaves, or four pages, of a book or manuscript.
2. Printing a book having pages of the largest size.

See -foli-.

WordReference Random House Unabridged Dictionary of American English © 2026

fo•li•o  (fō′lē ō′), n., pl. -li•os, adj., v., -li•oed, -li•o•ing. 
n. 

1. Printing a sheet of paper folded once to make two leaves, or four pages, of a book or manuscript.
2. Printing a volume having pages of the largest size, formerly made from such a sheet.
3. Printing a leaf of a manuscript or book numbered only on the front side.
4. [Print.]
   • Printing (in a book) the number of each page.
   • Printing (in a newspaper) the number of each page together with the date and the name of the newspaper.
5. Business [Bookkeeping.] a page of an account book or a left-hand page and a right-hand page facing each other and having the same serial number.
6. Law a certain number of words, in the U.S. generally 100, taken as a unit for computing the length of a document.

adj. 

7. Printing pertaining to or having the format of a folio:
   a folio volume.

v.t. 

8. Printing to number each leaf or page of.
9. Law to mark each folio in (a pleading or the like) with the proper number.

• Latin foliō (origin, originally in phrase in foliō in a leaf, sheet), ablative of folium folium
• 1525–35

Collins Concise English Dictionary © HarperCollins Publishers::

folio / ˈfəʊlɪəʊ/ noun ( -lios)

1. a sheet of paper folded in half to make two leaves for a book or manuscript
2. a book or manuscript of the largest common size made up of such sheets
3. a leaf of paper or parchment numbered on the front side only
4. a page number in a book
5. a unit of measurement of the length of legal documents, determined by the number of words, generally 72 or 90 in Britain and 100 in the US

adjective

1. relating to or having the format of a folio: a folio edition

Etymology: 16th Century: from Latin phrase in foliō in a leaf, from folium leaf