signal
(sĭg′nəl)
1. An indicator, such as a gesture or colored light, that serves as a means of communication
2. A message communicated by such means
3. Something that incites action
4. An impulse or fluctuating quantity, as of electrical voltage or light intensity, whose variations represent coded information
5. A sequence of digital values whose variations represent coded information
6. The sound, image, or message transmitted or received by means of telecommunications
7. Notably out of the ordinary