: a part that fits into the cylinder head of an internal combustion engine and carries two electrodes separated by an air gap across which the current from the ignition system discharges to form the spark for combustion
2
: one that initiates or gives impetus to an undertaking
Recent Examples on the WebSteinberg holds up a small plastic wing attached to a metal piece shaped like a spark plug. Dominic Smith, Scientific American, 7 Sep. 2022 Some still see Eddie Van Halen as the trim, suspenders-wearing spark plug with long, tousled brown hair and an impish, thousand-watt grin. Blair R. Fischer, Rolling Stone, 3 July 2022 The severe temperature and pressure also blew off the ground strap at the end of the spark plug, and even the cast-iron cylinder liner showed some pitting. Dave Vanderwerp, Car and Driver, 26 Aug. 2022 The first was Patient X, a former Marine, who was bit by his pet rattlesnake and attempted treatment by attaching spark plug wires to his lip and applying a jolt of electricity. Scott Lafee, San Diego Union-Tribune, 26 July 2022 Which goes back to Harris, the Braves’ 6-foot spark plug of 195 pounds. Terence Moore, Forbes, 28 June 2022 Their lead increased to 5-2 with a two-run homer in the fourth from Roc Riggio, who was the spark plug all day going 8 for 15 with two homers, three doubles, 10 RBIs and five runs scored. Jacob Unruh, USA TODAY, 6 June 2022 Diallo, 23, started 29 of his 58 games played, and found his niche has a spark plug and slasher. Omari Sankofa Ii, Detroit Free Press, 25 Mar. 2022 The Sox found a way to rally without their offensive spark plug, beating the Cubs 5-4 in 12 innings. Lamond Pope, Chicago Tribune, 30 May 2022 See More