Folio
in printing: (1) The running number of the pages of a book. The even folios are on the left-hand pages, the odd upon the right. The folios of prefatory matter are frequently in lower case Roman numerals. (2) A sheet of paper once folded. (3) A book of the largest size, whose sheets are folded but once, four pages to the sheet; hence it is used generally for any large volume or work. In bookkeeping, a page or opening in an account book. In law, a certain number of words in legal documents. The number varies in the States; thus in some of them, as in England, in low law documents, conveyances, deeds, etc., the folio is 72 words; in chancery and parliamentary proceedings 90 words. In New York and other States 100 words constitute a folio.