from the GNU version of the Collaborative International Dictionary of English
- n. A device utilized 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.
from The Century Dictionary and Cyclopedia
- n. A form of telegraph-or telephone-receiver, invented by Edison, depending for its action on the variation of the friction between two conductors in relative motion, when a current of electricity is passed from one to the other across the surface of contact.
Sorry, no etymologies found.