brake light vs visual signal

brake light and visual signal both are nouns.

Word	Noun	Adjective	Verb	Adverb
brake light	Yes	No	No	No
visual signal	Yes	No	No	No

As nouns, visual signal is a hypernym of brake light; that is, visual signal is a word with a broader meaning than brake light:

brake light: a red light on the rear of a motor vehicle that signals when the brakes are applied to slow or stop
visual signal: a signal that involves visual communication

brake light (noun)	visual signal (noun)
a red light on the rear of a motor vehicle that signals when the brakes are applied to slow or stop	a signal that involves visual communication