Definition of "caster"
caster
/ˈkɑːstə(ɹ)/
noun
plural casters
A wheeled assembly attached to a larger object at its base to facilitate rolling. A caster usually consists of a wheel (which may be plastic, a hard elastomer, or metal), an axle, a mounting provision (usually a stem, flange, or plate), and sometimes a swivel (which allows the caster to rotate for steering).
A shaker with a perforated top for sprinkling condiments such as sugar, salt, pepper, etc.