Electrical noise caused in a circuit by the thermal agitation, and subsequent random motion, of the charge carriers in a conductor.
Also called Johnson–Nyquist noise, Nyquist noise, or thermal noise.
1920s. From the name of John Bertrand Johnson, Swedish-born U.S. physicist, who published an account of it in 1928 (‘Thermal Agitation of Electricity in Conductors’, Phys. Rev 32 97 ff.) + noise.