oyster bed vs workplace

oyster bed and workplace both are nouns.

Word	Noun	Adjective	Verb	Adverb
oyster bed	Yes	No	No	No
workplace	Yes	No	No	No

As nouns, workplace is a hypernym of oyster bed; that is, workplace is a word with a broader meaning than oyster bed:

Other hypernyms of oyster bed include work.

oyster bed (noun)	workplace (noun)
a workplace where oysters are bred and grown	a place where work is done