See also: sparkplug
- The part of an internal combustion engine which forms a high-voltage electric spark which ignites the fuel-air mixture to begin the power stroke.
1919 January 1, Practical hints on running a gas engine, United States Department of Agriculture:
- With all engines using spark plugs it is comparatively easy to ascertain whether the ignition system is working properly.
- (figuratively) Someone who is a driving force in new endeavours.
2003, Growing for Market: News and Ideas for Market Gardeners:
- Steve Pincus, a Madison-area farmer who sells produce to L'Etoile, says admiringly of Odessa: "She's a spark plug. She's out there speaking out about sustainable agriculture and local food."
part of an internal combustion engine