plural of signal box

A building, typically adjacent to or spanning a railway line, from where signals, points and (sometimes) level crossings are controlled. / The alarm-box of a police or fire-alarm system.

(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

plural of block signal

(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.

(derogatory, chiefly in the context of political and social justice issues) The practice of expressing a particular opinion or performing a particular action in an attempt to make oneself look virtuous: commonly defensively in response to, or anticipation of, criticism; or aggressively, in assuming a moral posture in attacking an opponent.

present participle of virtue signal