bedframe vs piece of furniture

bedframe and piece of furniture both are nouns.

Word	Noun	Adjective	Verb	Adverb
bedframe	Yes	No	No	No
piece of furniture	Yes	No	No	No

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

bedframe: the framework of a bed
piece of furniture: furnishings that make a room or other area ready for occupancy

Other hypernyms of bedframe include article of furniture, furniture.

bedframe (noun)	piece of furniture (noun)
the framework of a bed	furnishings that make a room or other area ready for occupancy