1. An internal-combustion engine in which an explosive mixture is drawn into the cylinder on the first stroke and is compressed and ignited on the second stroke; work is done on the third stroke and the products of combustion are exhausted on the fourth stroke
   "Most modern car engines are four-stroke internal-combustion engines";
   - four-stroke engine

Derived forms: four-stroke internal-combustion engines

Type of: ICE, internal-combustion engine