spark plug

Fetched 2026-10-26 (cache).

Synonyms: sparkplug, spark plugs

Antonyms: sparkplug, spark plugs

Related words from Datamuse; suggestions, not definitions.

Noun

1. {{senseid|en|Q193340}} The part of some [[internal combustion engine]]s which forms a high-voltage [[electric]] [[spark]] which [[ignite]]s the fuel-air mixture to begin the [[power stroke]]. {{n-g|(Petrol engines have spark plugs. Diesel engines do not have them because the heat from their high [[compression ratio]]s supplies the ignition.)}}
2. {{lb|en|figuratively}} Someone who is a [[driving force]] in new [[endeavour]]s.
3. {{lb|en|military}} A rod (for cylindrical secondaries) or sphere (for spherical secondaries) of [[fissile]] material at the center of the [[secondary]] of a multistage [[thermonuclear weapon]], which undergoes [[nuclear fission]] when compressed to [[supercriticality]] by the imploding secondary, helping to raise the secondary to the pressures and temperatures necessary to ignite [[nuclear fusion]] in the secondary's fusion fuel.

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.