society > communication > indication > signalling > visual signalling > luminous signals > [verb (transitive)] > signal (something) by flashing light (3)
To express, utter, or communicate by a flash or flashes; esp. in modern use, to send (a message) along the wires of a telegraph.
transitive. To emit (radiance, flashes, or beams) rapidly and intermittently; to communicate (a message or signal) in this way.
To give (a signal), express (a message), etc. by means of flashlights.