steam engine

American  

noun

1. an engine worked by steam, typically one in which a sliding piston in a cylinder is moved by the expansive action of the steam generated in a boiler.

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steam-engine British  

noun

1. an engine that uses the thermal energy of steam to produce mechanical work, esp one in which steam from a boiler is expanded in a cylinder to drive a reciprocating piston

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steam engine Scientific  

1. An engine in which the energy of hot steam is converted into mechanical power, especially an engine in which the force of expanding steam is used to drive one or more pistons. The source of the steam is typically external to the part of the machine that converts the steam energy into mechanical energy.

2. Compare internal-combustion engine

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Other Word Forms

• steam-engine adjective

Etymology

Origin of steam engine

First recorded in 1745–55

Example Sentences

We also approach the 250th anniversary of James Watt’s first commercial steam engine going on-line in March 1776, starting an industrial revolution.

From Barron's • Jan. 13, 2026

He highlighted an example from history - James Watt is synonymous with the steam engine, even though he improved it rather than invented it.

From BBC • Jan. 28, 2025

It sat next to a steam engine dubbed “Old Dinah” that eventually replaced the mule teams.

From Los Angeles Times • May 15, 2024

The locomotive — often described as the world’s most famous steam engine — was scheduled to run short trips this weekend from the station as part of its centenary celebrations.

From Seattle Times • Sep. 30, 2023

The steam engine gave another hiss, and the wheels began to roll.

From "The Detective's Assistant" by Kate Hannigan