A bondage hood is a hood whose primary purpose is to allow the head of the victim to be secured as part of a BDSM scene involving bondage. Bondage hoods are made from heavy grade leather and will have D-rings in various locations to allow rope or chains to be attached to the hood. A bondage hood can also be used to describe a hood that can be locked on to the wearer to prevent 'unauthorised' removal. The most common design uses a lockable collar around the neck which prevents tampering with the zip/lacing.
Bondage hoods will usually incorporate elements of other hood designs such as gimp masks and isolation hoods. For this reason the term bondage hood is often used as a catch all phrase for any hood designed to be worn by a sub in a BDSM scene.