castor vs shaker

castor and shaker both are nouns.

Word	Noun	Adjective	Verb	Adverb
castor	Yes	No	No	No
shaker	Yes	No	No	No

As nouns, shaker is a hypernym of castor; that is, shaker is a word with a broader meaning than castor:

castor (noun)	shaker (noun)
a hat made with the fur of a beaver (or similar material)	a container in which something can be shaken
a pivoting roller attached to the bottom of furniture or trucks or portable machines to make them movable	a person who wields power and influence
a shaker with a perforated top for sprinkling powdered sugar