Wordnet 3.0
NOUN (1)
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;
[syn: four-stroke engine, four-stroke internal-combustion engine]
WordNet (r) 3.0 (2006):
four-stroke engine
n 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 [syn: four-stroke engine,
four-stroke internal-combustion engine]