noun

• An apparatus for transmitting and reproducing photographs or other images telegraphically, in which a photograph printed in such a way that its thickness varies with the darkness of the image is physically scanned with a stylus to produce a variable electrical signal, which can then be reproduced as an image on photographic paper using a beam of light that varies in intensity as a function of the signal.

  This apparatus was invented by Swiss photographer Édouard Belin (1876–1963).