lambert vs illumination unit

lambert and illumination unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
lambert	Yes	No	No	No
illumination unit	Yes	No	No	No

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

lambert: a cgs unit of illumination equal to the brightness of a perfectly diffusing surface that emits or reflects one lumen per square centimeter
illumination unit: a measure of illumination

lambert (noun)	illumination unit (noun)
a cgs unit of illumination equal to the brightness of a perfectly diffusing surface that emits or reflects one lumen per square centimeter	a measure of illumination