heliograph

views updated May 29 2018

he·li·o·graph / ˈhēlēəˌgraf/ • n. 1. a signaling device by which sunlight is reflected in flashes from a movable mirror. ∎  a message sent in such a way; a heliogram.2. a telescopic apparatus for photographing the sun.3. hist. a type of early photographic engraving made using a sensitized silver plate and an asphalt or bitumen varnish.• v. [tr.] 1. dated send (a message) by heliograph.2. hist. take a heliographic photograph of.DERIVATIVES: he·li·o·graph·ic / ˌhēlēəˈgrafik/ adj.he·li·og·ra·phy / ˌhēlēˈägrəfē/ n.