A sheet of paper, parchment, or other material folded in half to make two leaves in a codex.
Mainly for manuscripts, a leaf (ie two pages). Manuscript pages are often traditionally physically marked with numbers, and referred to, by folio number, with "recto" for the first side and "verso" for the second - so "f.3v" would be "page 6" in a conventional count.
Book size, or Paper size, where folio is a book bound from folio sheets, usually 15" (38,1 cm) tall or more.
FOLIO:, a monthly magazine covering the publishing industry.
Folio Corporation, a software company, and technology product created in the mid-1980s in Orem, Utah. The product is used to provide full-text indexing and search for unstructured text. Known for its use of underhead technology which compresses text and index into a single information-base called an "infobase" and commly referred to as an NFO. The product has been used largely in the professional publishing industry and is currently (2008) being used by over 1,000 organizations world-wide. The technology is now owned by Microsoft through their acquisition of previous owner Fast Search & Transfer.
Folio:, A new wave band from Los Angeles California.