heliograph
pronunciation
How to pronounce heliograph in British English:
UK [ˈhi:liəgrɑ:f]
How to pronounce heliograph in American English:
US [ˈhiliəgræf]
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- Noun:
- an apparatus for sending telegraphic messages by using a mirror to turn the sun's rays off and on
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- Verb:
- signal by means of a mirror and the using the sun's rays
Word Origin
- heliograph (n.)
- 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.