- a red lamp, used as a traffic signal to mean “stop.”
- an order or directive to halt an action, project, etc.: There’s a red light on all unnecessary expenses.
- a children’s running game in which players must stop when “Red light!” is called.
- a signal of danger; warning.
verb (used with object), red-light·ed, red-light·ing.
- Informal. to stop or deter by means of or as if with a red light.
- a signal to stop, esp a red traffic signal in a system of traffic lights
- a danger signal
- an instruction to stop or discontinue
- a red lamp in a window of or outside a house indicating that it is a brothel
- (as modifier)a red-light district