1. (安装在家具底部的)脚轮，滚轮
Castors are small wheels fitted to a piece of furniture so that it can be moved more easily.

1. a hat made with the fur of a beaver (or similar material)

Synonym: beaver

2. a pivoting roller attached to the bottom of furniture or trucks or portable machines to make them movable

Synonym: caster

3. a shaker with a perforated top for sprinkling powdered sugar

Synonym: caster