pis‧ton /ˈpɪstən/ noun [countable]
[Date: 1700-1800; Language: French; Origin: Italian pistone 'large stick for crushing', from pistare 'to crush']
a part of an engine consisting of a short solid piece of metal inside a tube, which moves up and down to make the other parts of the engine move

[TahlilGaran] Dictionary of Contemporary English ▲