(economics) A sign, attached to a commodity and concerning its price, that is intended to increase demand for it

(rail transport) A signal set at danger and showing a red light or other stop indication, which a train driver must not pass until it changes or until manually cleared past the signal by a dispatcher.

Alternative spelling of danger signal.

plural of signalling pathway

(neologism) Somebody who engages in virtue signalling.

Alternative form of time signal

An American crayfish, Pacifastacus leniusculus, having a large claw that it waves to attract a mate.

A transmitter encodes data by producing a signal which is a continuous stream of signalling events each which has sufficient information for the receiver to recover the original data. Just like a quantum leap is the smallest measurable leap, a signalling event is the smallest possible amount of signal that the receiver needs to recover the original data without error.

Alternative spelling of smoke signal

(often pluralized) A method of long-distance communication sometimes used in ancient and undeveloped societies, consisting of messages conveyed by means of columns or intermittent puffs of smoke.