Binder

1. One who binds; as, a binder of sheaves; one whose trade is to bind; as, a binder of books.
2. Anything that binds, as a fillet, cord, rope, or band; a bandage; -- esp. the principal piece of timber intended to bind together any building.
3. a pair of stiff oblong covers, sometimes detachable, designed for insertion of paper pages to create a book-like document, such as in a loose-leaf binder.