A signal may refer to:

• an abstract element of information, or, more exactly, usually a flow of information (in either one or several dimensions). See Signal (information theory).
• (in electronics) a signal is any physical phenomenon that can be modeled as a function from time or position. Signals carry information: Analog signals are continuous while digital signals are discrete (see signal processing and noise (physics)).
• Signal related to computing, See signal (computing)
• (in the streets) a means of controlling road vehicles, pedestrians or trains (see Traffic signal, Pedestrian crossing or Railway signal).
• (in a partnership card game) a player's choice of card to play at a particular time, which gives information to a partner, in a partnership card game (see signal (bridge)).
• Signal was also a German Wehrmacht propaganda newspaper during World War II.
• Signal 1 and Signal 2 are local radio stations operated by the Wireless Group in Stoke-on-Trent, England.
• In economics, a signal describe a way of credibly conveying information from one party to another. See signaling, Michael Spence.
• A brand of toothpaste.
• A discontinued brand of NCR paper.
• Signal is a Bulgarian rock band.