saddlebag

名词noun

1. 1A covered pouch, usually one of a pair, laid across the back of a horse, donkey, or mule behind its saddle, or hanging over the rear wheel of a motorcycle; often made of leather or (on a motorcycle) a rigid material.
2. 2(cycling, nonstandard, by extension) pannier
3. 3(cycling) A seat pack or a seat bag (a pouch or a small bag attached to the seat or seat post of a bicycle)