A leaf of a book or manuscript.
folio in U.S. law
• A page of a book, that is, one side of a leaf of a book.
• A page number. The even folios are on the left-hand pages and the odd folios on the right-hand pages. A sheet of paper folded in half. A book made of sheets of paper each folded in half (two leaves or four pages to the sheet); hence, a book of the largest kind, exceeding 30 centimetres in height.
• A page number. The even folios are on the left-hand pages and the odd folios on the right-hand pages.
• A sheet of paper folded in half.
• A book made of sheets of paper each folded in half (two leaves or four pages to the sheet); hence, a book of the largest kind, exceeding 30 centimetres in height.
• A wrapper for loose papers.
• A page in an account book; sometimes, two opposite pages bearing the same serial number.
• A protective case with a flap that folds to cover the screen of a mobile device.
• A leaf containing a certain number of words; hence, a certain number of words in a piece of writing, as in England, in law proceedings 72, and in chancery, 90; in New York, 100 words. .mw-parser-output .defdate{font-size:smaller}
(Verb) To put a serial number on (a folio or page, or on all the folios or pages of a book); to foliate, to page.
The practical impact of folio
folio appears in U.S. legal practice across multiple practice areas. Knowing what it means — and when it applies — can determine the outcome of motions, filings, and negotiations. For non-lawyers, the value of looking up a precise definition is that legal terms often carry meanings that differ from everyday usage; relying on the common meaning can lead to costly missteps.
folio — procedural details
In practice, folio is invoked when parties, judges, or attorneys need to identify the legal status of an issue, the rights of those involved, or the procedural step required next. The definition shown above is sourced from Wiktionary , which is widely cited in U.S. legal practice. Because U.S. law is jurisdictionally layered — federal, state, and sometimes local — the precise application of the term can vary by court, so check the controlling authority for your specific case.