plural of signal phrase

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

A gang sign.

a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day

A traffic light.

(endocrinology) A type of cell signaling involving the release of a hormone from a nerve cell that has an effect on another cell.

(biochemistry) A series of chemical reactions within a cell which start when a transmembrane protein comes into contact with a chemical signal, resulting in a second messenger being triggered.

The meaning of a railway signal

(rail transport) The visual appearance of a railway 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.