\Co*her"er\, n. (Elec.)
Any device in which an imperfectly conducting contact between
pieces of metal or other conductors loosely resting against
each other is materially improved in conductivity by the
influence of Hertzian waves; -- so called by Sir O. J. Lodge
in 1894 on the assumption that the impact of the electic
waves caused the loosely connected parts to cohere, or weld
together, a condition easily destroyed by tapping. A common
form of coherer as used in wireless telegraphy consists of a
tube containing filings (usually a pinch of nickel and silver
filings in equal parts) between terminal wires or plugs
(called
{conductor plugs}).