spark plug


Definition of spark plug 

1 : 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

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Other Words from spark plug

sparkplug \ˈspärk-ˌpləg \ transitive verb

Examples of spark plug in a Sentence

Recent Examples on the Web

The senior guard hasn't been at 100% while dealing with a turf toe injury, but he's been a warrior and the spark plug during the Red Raiders' advancement. Scott Gleeson, USA TODAY, "NCAA tournament Sweet 16: Most important players for every March Madness team," 20 Mar. 2018 Shane Victorino, a Rule 5 draft pick who became the spark plug of a World Series champion, plans to retire next month after signing a one-day contract with the Phillies. Matt Breen,, "Shane Victorino to sign one-day contract, retire as a Phillie in August celebration," 3 July 2018 The Ecuadorian spark plug tallied the decisive score on a penalty kick in the 78th minute, inching the ball past United keeper David Ousted’s outstretched arms into the top-right pocket. Owen Pence,, "Revolution hold off D.C. United," 1 July 2018 Every team can use a player like Stephenson — a gritty, versatile defender who served as a spark plug off the bench during his second stint in Indiana. Sam Amick, USA TODAY, "LeBron James, Paul George and the top 40 NBA free agents of 2018," 28 June 2018 Usually knocking is what happens when the air-fuel mixture in an engine combusts when it’s not supposed to, usually because a spark plug is malfunctioning and little pockets of air are exploding because of pressure rather than spark. Matt Jancer, Popular Mechanics, "How a Knocking Engine Is the Sign of Automotive Innovation," 11 May 2018 Headlights or not, the alternator is always making electricity to fire the spark plugs and recharge the battery. Ray Magliozzi,, "Car Talk: Neighbor's Dangerous Habit Is Driving With His Lights Off," 15 June 2018 Shortstop and leadoff man Cavan Tully has been the squad’s offensive spark plug. Rick O'brien,, "Council Rock North has flourished on the road in PIAA District 1 baseball playoffs," 26 May 2018 Over the past 30, however, Goldstein has been the spark plug for Huntley (32-6). Paul Johnson, Elgin Courier-News, "Goldstein rush: Senior shortstop Jordan Goldstein transforms at plate in leading Huntley to state semifinals," 7 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'spark plug.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of spark plug

1903, in the meaning defined at sense 1

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Last Updated

6 Oct 2018

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Time Traveler for spark plug

The first known use of spark plug was in 1903

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More Definitions for spark plug

spark plug


English Language Learners Definition of spark plug

: a part of an engine that produces a spark that makes the fuel burn

spark plug


Kids Definition of spark plug

: a device used in an engine to produce a spark that ignites a fuel mixture

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