1
a
: the hot gas that is created when water is boiled
Careful, the steam from the pot is hot.
b
: steam that is created by a machine and kept under pressure to provide power
Steam drives the turbines.
a steam-powered engine
The boat runs on steam.
—often used before another nouna steam engine/train
2
: very small drops of water that form on a surface when warm air that contains a lot of water is cooled down
He wiped the steam from the mirrors.
3
informal
: the strength, force, or energy that allows something or someone to continue, to go faster, etc.
Sales have lost steam [=have slowed down] in recent weeks.
The campaign quickly gained/gathered steam. [=became more popular and successful]
He was afraid he would run out of steam before the end of the race.
I was making good progress this morning, but now I'm starting to run out of steam.
The project is slowly picking up steam. [=slowly beginning to move ahead in a faster and more effective way]
steams; steamed; steaming
1
: to produce steam
a steaming bowl of soup
2
: to cook, heat, or treat (something) with steam
She prefers to steam carrots rather than boil them.
steamed vegetables
3
: to cause (something, such as a piece of glass) to become covered with small drops of water
Their breath steamed the windows.
—usually + upTry not to steam up your glasses.
The windows were all steamed up.
My glasses steamed up [=fogged up] when I came indoors from the cold.
4
always followed by an adverb or preposition
a
: to move by using power produced by steam
The ship steamed into port.
We steamed up the river. [=we went up the river on a ship powered by steam]
b
: to move forward in a quick and forceful way
He steamed into the room and began shouting orders.
—sometimes used figurativelyOur plans are steaming ahead.
Cite this Entry
“Steam.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/steam. Accessed 15 Apr. 2026.
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