traffic light vs traffic signal

traffic light and traffic signal both are nouns.

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

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

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

Other synonyms of traffic light include stoplight.

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