The Collaborative International Dictionary of English v.0.48:
Binding \Bind"ing\, a. That binds; obligatory. [1913 Webster] Binding beam (Arch.), the main timber in double flooring. Binding joist (Arch.), the secondary timber in double-framed flooring. [1913 Webster] Syn: Obligatory; restraining; restrictive; stringent; astringent; costive; styptic. [1913 Webster]