[ hee-lee-uh-graf, -grahf ]
/ ˈhi li əˌgræf, -ˌgrɑf /


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 forms

he·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

British Dictionary definitions for heliograph


/ (ˈhiːlɪəʊˌɡrɑːf, -ˌɡræf) /


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 Forms

heliographer (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