baby bed vs piece of furniture

baby bed and piece of furniture both are nouns.

Word	Noun	Adjective	Verb	Adverb
baby bed	Yes	No	No	No
piece of furniture	Yes	No	No	No

As nouns, piece of furniture is a hypernym of baby bed; that is, piece of furniture is a word with a broader meaning than baby bed:

baby bed: a small bed for babies; enclosed by sides to prevent the baby from falling
piece of furniture: furnishings that make a room or other area ready for occupancy

Other hypernyms of baby bed include article of furniture, furniture.

baby bed (noun)	piece of furniture (noun)
a small bed for babies; enclosed by sides to prevent the baby from falling	furnishings that make a room or other area ready for occupancy