Spark gap

1.

(Elec.) The space filled with air or other dielectric between high potential terminals (as of an electrostatic machine, induction coil, or condenser), through which the discharge passes; the air gap of a jump spark.

Noun	1.	spark gap - a component of an ignition system; consists of two shaped electrodes and the space between them
	2.	spark gap - the gap between two high-potential terminals

component, constituent, element, ignition, ignition system