Fol"io (?), n.; pl. Folios (#). [Ablative of L. folium leaf. See 4th Foil.]
1.
A leaf of a book or manuscript.
2.
A sheet of paper once folded.
3.
A book made of sheets of paper each folded once (four pages to the sheet); hence, a book of the largest kind. See Note under Paper.
4. (Print.)
The page number. The even folios are on the left-hand pages and the odd folios on the right- hand.
5.
A page of a book; (Bookkeeping) a page in an account book; sometimes, two opposite pages bearing the same serial number.
6. (Law)
A leaf containing a certain number of words, hence, a certain number of words in a writing, as in England, in law proceedings 72, and in chancery, 90; in New York, 100 words.
Folio post, a flat writing paper, usually 17 by 24 inches.
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Fol"io, v. t.
To put a serial number on each folio or page of (a book); to page.
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Fol"io, a.
Formed of sheets each folded once, making two leaves, or four pages; as, a folio volume. See Folio, n., 3.
© Webster 1913