Definition of two-stroke in US English:



  • 1Denoting an internal combustion engine whose power cycle is completed in one up-and-down movement of the piston.

    • ‘Mowers powered by two-stroke engines, for which gasoline and oil are mixed prior to ignition, are dirtiest.’
    • ‘According to the EPA, two-stroke engines - which power a variety of other watercraft as well - are a leading source of toxic water pollution.’
    • ‘Myriads of old cars, beat-up buses and superannuated trucks asphyxiate urban areas with their deadly exhaust, while the dirty two-stroke engines that power small vehicles emit ten times as much fine particulate matter as modern cars.’
    • ‘However, instead of a large battery to power an electric motor, you have a fuel tank and a small piston engine, usually two-stroke, complete with air-filter, carburettor and exhaust pipe.’
    • ‘See also the articles on Hemi engines, rotary engines and two-stroke engines.’
    1. 1.1 Denoting a vehicle having a two-stroke engine.
      • ‘The two-stroke scooter engine was replaced by a more robust 247 cc four-stroke one.’
      • ‘You're referring here to two-stroke vehicles and we haven't ourselves done very many trials on these but we are very hopeful.’
      • ‘The race was split into four categories 50 cc, four-stroke motorcycles up to 180 cc, novice riders on two-stroke bikes and 100 to 135 cc for the experienced.’
      • ‘Two-wheeler maker TVS Motor Company has said it plans to replace two-stroke motorcycle ‘Max’ with a four-stroke entry-level motorcycle within six months to arrest the erosion in sales.’
      • ‘A two-stroke gasoline-fueled Honda motorcycle using HCCI principles finished seventh overall in the 1995 Baja 1000 off-road race.’


  • A two-stroke engine or vehicle.

    Compare with four-stroke
    • ‘He and his team created the Evinrude E-TEC family of two-strokes; engines that are clean and darn-near worry free.’
    • ‘Four-strokes just run so much cleaner than the old two-strokes.’
    • ‘I had some good performances on 500 cc two-strokes in 1998 and 1999 but some still weren't convinced that I could win on the big bikes.’
    • ‘Four-stroke engines are heavier than two-strokes but the technology means they burn fuel more completely and emit fewer pollutants.’
    • ‘The fuel is better atomized than with carbureted two-strokes, resulting in a cleaner, more complete burn, more efficiency and better power, all of which helps these hybrids to meet EPA regulations.’



/ˈtu ˌstroʊk//ˈto͞o ˌstrōk/