sideflash

from The Century Dictionary.

• noun In electricity, the disruptive discharge between neighboring parts of a bent conductor which sometimes occurs in the case of oscillatory currents of high frequency; the spark between a lightning-rod and neighboring masses of metal induced by an oscillatory discharge of lightning.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Elec.) A disruptive discharge between a conductor traversed by an oscillatory current of high frequency (as lightning) and neighboring masses of metal, or between different parts of the same conductor.