lamp vs source of illumination

lamp and source of illumination both are nouns.

Word	Noun	Adjective	Verb	Adverb
lamp	Yes	No	No	No
source of illumination	Yes	No	No	No

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

lamp: an artificial source of visible illumination
source of illumination: any device serving as a source of visible electromagnetic radiation

lamp (noun)	source of illumination (noun)
an artificial source of visible illumination	any device serving as a source of visible electromagnetic radiation
a piece of furniture holding one or more electric light bulbs