motograph

English

Etymology

moto- +‎ -graph

Noun

motograph (plural motographs)

1. (historical) A device used in the making of a loud-speaking telephone, depending on the fact that the friction between a metallic point and a moving cylinder of moistened chalk, or a moving slip of paper, on which it rests is diminished by the passage of a current between the point and the moving surface.

Anagrams

• photogram, tomograph