castor
(also caster), n
1 any of the small swivelling wheels fixed to the bottom of a piece of furniture so that it can be moved easily (家具的)小脚轮. =>illus at App 1 见附录1之插图, page xvi.
2 small container with holes in the top for sprinkling sugar, etc 调味瓶(顶端有小孔, 用以撒糖等).