A piece of parchment which is folded to create two leaves.
two leaves (four pages) formed by a single folded sheet of vellum or paper
A single sheet of parchment, paper, or papyrus that has been folded in two to form four writing surfaces.
A sheet of paper (or vellum) folded once, forming two sheets joined at the fold (or joint).
two pages from a book formed from a single sheet of parchment folded down the middle
bifolia: sheet of parchment or paper folded to form two leaves or four pages in codex.