Pronunciation: (hē'lē-u-graf", -gräf"), [key]
1. a device for signaling by means of a movable mirror that reflects beams of light, esp. sunlight, to a distance.
3. Meteorol.an instrument for recording the duration and intensity of sunshine.
4. Photog., Print.an early type of photoengraving made on a metal plate coated with sensitized asphalt.
to communicate by heliograph.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.