lamp vs piece of furniture

lamp and piece of furniture both are nouns.

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

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

lamp: a piece of furniture holding one or more electric light bulbs
piece of furniture: furnishings that make a room or other area ready for occupancy

Other hypernyms of lamp include article of furniture, furniture.

lamp (noun)	piece of furniture (noun)
an artificial source of visible illumination	furnishings that make a room or other area ready for occupancy
a piece of furniture holding one or more electric light bulbs