traffic signal vs traffic light

traffic signal and traffic light both are nouns.

Word	Noun	Adjective	Verb	Adverb
traffic signal	Yes	No	No	No
traffic light	Yes	No	No	No

As nouns, traffic signal and traffic light are synonyms defined as:

traffic signal and traffic light: a visual signal to control the flow of traffic at intersections

Other synonyms of traffic signal include stoplight.

traffic signal (noun)	traffic light (noun)
a visual signal to control the flow of traffic at intersections	a visual signal to control the flow of traffic at intersections