spark plug


noun

a device designed to fit in each cylinder of a gasoline-powered internal-combustion engine and to produce the electric spark for igniting the mixture of gasoline and air.
Informal. a person who leads, inspires, or animates a group.

Nearby words

  1. spark erosion,
  2. spark gap,
  3. spark generator,
  4. spark off,
  5. spark photography,
  6. spark spectrum,
  7. spark transmitter,
  8. spark-killer,
  9. sparker,
  10. sparkie

Origin of spark plug

First recorded in 1900–05

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for spark plug


British Dictionary definitions for spark plug

spark plug

noun

another name for sparking plug
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for spark plug

spark plug

A device in the cylinder head of an internal-combustion engine that ignites the fuel mixture by means of an electric spark. Spark plugs consist of two electrodes that are separated by an insulator except at their tips. When high voltage electricity is fed to one electrode, it jumps across the gap from one tip to the other as a spark. The voltage required to generate a spark is directly proportional to the size of the gap; in a car engine it is about 18,000 volts.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.