crown lens vs lens system

crown lens and lens system both are nouns.

Word	Noun	Adjective	Verb	Adverb
crown lens	Yes	No	No	No
lens system	Yes	No	No	No

As nouns, lens system is a hypernym of crown lens; that is, lens system is a word with a broader meaning than crown lens:

crown lens: a lens made of optical crown glass
lens system: a transparent optical device used to converge or diverge transmitted light and to form images

Other hypernyms of crown lens include lens, lense.

crown lens (noun)	lens system (noun)
a lens made of optical crown glass	a transparent optical device used to converge or diverge transmitted light and to form images