from The Century Dictionary.
- noun A discharge between the terminals of an electrical machine under conditions such that the dielectric is rendered luminous although no sparks appear. The term is sometimes used to designate the luminous discharge in vacuum-tubes as well as the discharge in air.
Sorry, no etymologies found.
They indicated a marked deficiency of thermal radiations, implying for coronal light, in Professor Langley's opinion,  an origin analogous to that of the electric glow-discharge, which, at low pressures, was found by K. Ångström in