Related Clues:
- Seven Wonders of the World lighthouse
- Wink, e.g.
- Optics topic
- Use a blinker
- It's at the end of a tunnel, proverbially
- Use the turn indicator
- Communication by sign
- Gesture, light or sound which sends a message
- Illumination weights little
- Indication or warning
- Illumination weighs very little
- Communication that encodes a message
- Sign that conveys a message
- Gesture to communicate
- Gesture of communication