Heliograph
WordNet
noun
(1) An apparatus for sending telegraphic messages by using a mirror to turn the sun's rays off and on
verb
(2) Signal by means of a mirror and the using the sun's rays
WiktionaryText
Noun
- An apparatus for signalling by means of a moveable mirror which reflects flashes of sunlight.
- A heliogram.
- An instrument for measuring the intensity of sunlight.
- A device for photographing the sun.
- A photograph.
Verb
- To send a message by heliograph.
- To send a heliograph.