Origin: 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. 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; a page in an account book; sometimes, two opposite pages bearing the same serial number.
6. 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.