folio

n.; pl. Folios [ Ablative of L. folium leaf. See 4th Foil. ] 1. A leaf of a book or manuscript. [ 1913 Webster ]

2. A sheet of paper once folded. [ 1913 Webster ]

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. [ 1913 Webster ]

4. (Print.) The page number. The even folios are on the left-hand pages and the odd folios on the right-hand. [ 1913 Webster ]

5. A page of a book; (Bookkeeping) a page in an account book; sometimes, two opposite pages bearing the same serial number. [ 1913 Webster ]

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. [ 1913 Webster ]

Folio post, a flat writing paper, usually 17 by 24 inches. [ 1913 Webster ]