noun photography.
2. heliography ·add. ·noun the description of the sun.
3. heliography ·add. ·noun the system, art, or practice of telegraphing, or signaling, with the heliograph.
4. heliography ·add. ·noun an early photographic process invented by nicephore niepce, and still used in photo-engraving. it consists essentially in exposing under a design or in a camera a polished metal plate coated with a preparation of asphalt, and subsequently treating the plate with a suitable solvent. the light renders insoluble those parts of the film which is strikes, and so a permanent image is formed, which can be etched upon the plate by the use of acid.