selenium cell vs electric eye

selenium cell and electric eye both are nouns.

Word	Noun	Adjective	Verb	Adverb
selenium cell	Yes	No	No	No
electric eye	Yes	No	No	No

As nouns, electric eye is a hypernym of selenium cell; that is, electric eye is a word with a broader meaning than selenium cell:

selenium cell: a photoelectric cell that uses a strip of selenium
electric eye: a transducer used to detect and measure light and other radiations

Other hypernyms of selenium cell include magic eye, photocell, photoconductive cell, photoelectric cell.

selenium cell (noun)	electric eye (noun)
a photoelectric cell that uses a strip of selenium	a transducer used to detect and measure light and other radiations