caster

1 :  one that casts; especially :  a machine that casts type

2 or castor play \-tər\ a :  a usually silver table vessel with a perforated top for sprinkling a seasoning (such as sugar or spice)b :  a usually revolving metal stand bearing condiment containers (such as cruets, mustard pot, and often shakers) for table use :  a cruet stand

3 :  any of a set of wheels or rotating balls mounted in a swivel frame and used for the support and movement of furniture, trucks, and portable equipment

4 :  the slight usually backward tilt from vertical of the axis of the steering mechanism of an automobile for giving directional stability to the front wheels