Learn how to say Heliograph correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word heliograph:
1a signalling device by which sunlight is reflected in flashes from a movable mirror.
a message sent by heliograph; a heliogram.
2a telescopic apparatus for photographing the sun.
3 historical a type of early photographic engraving made using a sensitized silver plate and an asphalt or bitumen varnish.
1send (a message) by heliograph:
the glasses seemed to be heliographing a warning
2 historical take a heliographic photograph of:
he could only heliograph static subjects in very intense light