bedstead vs piece of furniture

bedstead and piece of furniture both are nouns.

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

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

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

Other hypernyms of bedstead include article of furniture, furniture.

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