[hee-lee-uh-graf, -grahf]


a device for signaling by means of a movable mirror that reflects beams of light, especially sunlight, to a distance.
Astronomy. photoheliograph.
Meteorology. an instrument for recording the duration and intensity of sunshine.
Photography, Printing. an early type of photoengraving made on a metal plate coated with sensitized asphalt.

verb (used with or without object)

to communicate by heliograph.

Origin of heliograph

First recorded in 1815–25; helio- + -graph
Related formshe·li·og·ra·pher [hee-lee-og-ruh-fer] /ˌhi liˈɒg rə fər/, nounhe·li·o·graph·ic [hee-lee-uh-graf-ik] /ˌhi li əˈgræf ɪk/, he·li·o·graph·i·cal, adjectivehe·li·o·graph·i·cal·ly, adverbhe·li·og·ra·phy, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for heliograph

Historical Examples of heliograph

  • Instantly, the ship shone like the polished mirror of a heliograph.

    Islands of Space

    John W Campbell

  • He had also been corroborated by a man who had seen the man who took it down from the heliograph.

  • The heliograph would be useless in stormy weather or in fog.

    El Diablo

    Brayton Norton

  • The Hussars left behind a Colt-Maxim and a heliograph for our usage.

  • If there is no sun I cannot heliograph and I have a host of signals to look up and get ready.

British Dictionary definitions for heliograph



an instrument with mirrors and a shutter used for sending messages in Morse code by reflecting the sun's rays
a device used to photograph the sun
Derived Formsheliographer (ˌhiːlɪˈɒɡrəfə), nounheliographic (ˌhiːlɪəʊˈɡræfɪk) or heliographical, adjectiveheliography, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for heliograph

product of a certain type of engraving process, 1853, from helio- + -graph "something written." Earlier, "a description of the sun" (1706, implied in heliographic). Heliography (1845 in the engraving sense) also (1840) was an early term for what came to be called photography.

Online Etymology Dictionary, © 2010 Douglas Harper