visual system vs sight

visual system and sight both are nouns.

Word	Noun	Adjective	Verb	Adverb
visual system	Yes	No	No	No
sight	Yes	No	Yes	No

visual system (noun)	sight (noun)
the sensory system for vision	the act of looking or seeing or observing
	the ability to see; the visual faculty
	an instance of visual perception
	the range of vision
	a range of mental vision
	a place of interest, especially to visitors
	anything that is seen
	(often followed by `of') a large number or amount or extent

visual system (verb)	sight (verb)
	catch sight of; to perceive with the eyes
	take aim by looking through the sights of a gun (or other device)