Traffic lights, also known as stop lights, usually refer to the column of three or more lights
that act as a signal to car drivers whether they can go, cannot go, or need to be cautious. These
lights are usually used at intersections to indicate which lanes can go so that cars don't
ram into each other. Not much more to them than that. Here are some pictures of them.
3-light traffic lights showing red, green, and yellow
3-left-arrow traffic lights showing red, green, and yellow