computer screen vs CRT screen

computer screen and CRT screen both are nouns.

Word	Noun	Adjective	Verb	Adverb
computer screen	Yes	No	No	No
CRT screen	Yes	No	No	No

As nouns, CRT screen is a hypernym of computer screen; that is, CRT screen is a word with a broader meaning than computer screen:

computer screen: a screen used to display the output of a computer to the user
CRT screen: the display that is electronically created on the surface of the large end of a cathode-ray tube

Other hypernyms of computer screen include screen.

computer screen (noun)	CRT screen (noun)
a screen used to display the output of a computer to the user	the display that is electronically created on the surface of the large end of a cathode-ray tube