(railways) One of the danger signals or safety signals which guide the movement of trains in a block system, often coupled with a switch so that opening or closing the switch also operates the signal.

(chiefly US, automotive) each of the flashing lights on each side of a vehicle which indicate a turn is being made to left or right, or a lane change etc.

plural of signal aspect

plural of signal indication

(rail transport) The visual appearance of a railway signal

The meaning of a railway signal

An indication that something is a paraphrase or direct quote. / A phrase that signals a particular meaning or stance.

A gang sign.

plural of signal phrase

(sciences) A figure of merit comparing the strength of a signal carrying information to the noise interfering with it.