1) Vehicle braking technology 
A drum brake is a brake that uses friction caused by a set of shoes or pads that press against a rotating drum-shaped part called a brake drum. The term drum brake usually means a brake in which shoes press on the inner surface of the drum. When shoes press on the outside of the drum, it is usually called a clasp brake. Where the drum is pinched b...
(from the article `automobile`) Originally, most systems for stopping vehicles were mechanically actuated drum brakes with internally expanding shoes; i.e., foot pressure exerted on ... ...against the inside of the rim. Front and rear brakes on other bikes are actuated by cables connected to a brake lever on each handlebar. Caliper ... ...
a brake consisting of two brake shoes mounted on a backing plate. One or two cams cause shoes to expand against inside of brake drum. Brake drum is part of hub or is bolted to hub.
[n] - hydraulic brake in which friction is applied to the inside of a spinning drum by the brake shoe
noun hydraulic brake in which friction is applied to the inside of a spinning drum by the brake shoe
A Drum Brake is the older style of motorcycle brake. Most bikes use disc brakes these days. Drum bra
a brake system in which a pair of brake shoes can be pressed against the inner surface of a shallow metal drum that is rigidly attached to a wheel.