Section (bookbinding)

In bookbinding, a section, gathering, or signature is a group of sheets folded in half, to be worked into the binding as a unit.

[1] The section is the basic building block of codex bindings.

The gatherings can be seen by looking at the top or bottom sides of the book, though cheaper modern books are perfect bound with no gatherings, each sheet glued directly to the binding.

In medieval manuscripts, a gathering, or quire, was most often formed of four folded sheets of vellum or parchment, i.e. 8 leaves, 16 sides.

A gathering made of a single folded sheet (i.e. two leaves, four sides) is a bifolium (plural bifolia); a gathering of two sheets (i.e. four leaves, eight sides) is a binion; and one of five sheets (10 leaves, 20 sides) is a quinion.