Heliograph

Origin

From - + graph + -.

Full definition of heliograph

Noun

1. An apparatus for signalling by means of a moveable mirror which reflects flashes of sunlight.
• 1979, Alasdair Gray, ‘Five Letters From an Eastern Empire’, Canongate 2012 (Every Short Story 1951-2012), p. 93:when we stood up at nightfall we saw, in the sunset, the sparkle of the heliograph above cities, on the far side of the horizon.
2. A heliogram.
3. An instrument for measuring the intensity of sunlight.
4. A device for photographing the sun.
5. (obsolete) A photograph.

Verb

1. (transitive) To send a message by heliograph.
2. (intransitive) To send a heliograph.

Derived terms

• heliographer
• heliographic
• heliography