Hub

In audio this is the term used for the circular center section of the reel upon which magnetic tape is wound; the remainder of the wheel being the flanges (usually round metal and shiny) which are attached to the hub. Professionals using open reel tape machines often purchase tape wound on only the hub without the flanges because it is less expensive. The expensive metal flanges can then be transferred and used from an older tape that is no longer in use. Tape sold is this fashion is commonly called a “pancake.”