mechanism
noun
mech·a·nism
ˈme-kə-ˌni-zəm 
1
a
: a piece of machinery (see machinery sense 1)
The camera's shutter mechanism is broken.
b
: a process, technique, or system for achieving a result
the mechanisms of peace—
F. D. Roosevelt
F. D. Roosevelt2
: mechanical operation or action : working sense 2
he acknowledges nothing besides matter and motion; so that all must be performed either by mechanism or by accident—Richard Bentley
Richard Bentley3
: a doctrine that holds natural processes (as of life) to be mechanically determined and capable of complete explanation by the laws of physics and chemistry
4
: the fundamental processes involved in or responsible for an action, reaction, or other natural phenomenon
meteorologists believe that this pressure jump is the mechanism responsible for storms and tornadoes—Think
compare defense mechanism
ThinkExamples of mechanism in a Sentence
The camera's shutter mechanism is broken.
Scientists are studying the body's mechanisms for controlling weight.
There is no mechanism in place for enforcing the new law.
a legal mechanism to prevent lobbyists from exerting unfair influence
psychological mechanisms for dealing with a tragic loss
Recent Examples on the Web
Replace people with mechanisms to drive labor costs down and profits up.
—Erik Sherman, Forbes.com, 26 July 2025
In a 1998 essay for The New Yorker, the author Arthur Miller described urbanites’ Depression-era coping mechanisms: People caught the breeze on open-air trolleys, climbed onto the back of ice trucks, and flocked to the beach.
—Yasmin Tayag, The Atlantic, 26 July 2025
After millions of years of primate evolution, TEs now make up almost half of the human genome thanks to their copy-and-paste-like mechanism.
—Stephanie Edwards, Discover Magazine, 24 July 2025
The tourbillon class—named for the intricate mechanism that keeps a watch’s guts constantly in motion—starts at $19,190.
—Chris Morris, Fortune, 24 July 2025
See All Example Sentences for mechanism
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Erik Sherman, Forbes.com, 26 July 2025
In a 1998 essay for The New Yorker, the author Arthur Miller described urbanites’ Depression-era coping mechanisms: People caught the breeze on open-air trolleys, climbed onto the back of ice trucks, and flocked to the beach.
—Yasmin Tayag, The Atlantic, 26 July 2025
After millions of years of primate evolution, TEs now make up almost half of the human genome thanks to their copy-and-paste-like mechanism.
—Stephanie Edwards, Discover Magazine, 24 July 2025
The tourbillon class—named for the intricate mechanism that keeps a watch’s guts constantly in motion—starts at $19,190.
—Chris Morris, Fortune, 24 July 2025
See All Example Sentences for mechanism
Cite this Entry
“Mechanism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mechanism. Accessed 29 Jul. 2025.
Copy CitationKids Definition
mechanism
noun
mech·a·nism
ˈmek-ə-ˌniz-əm
1
: a piece of machinery
2
a
: the parts by which a machine operates
b
: the process, way, or system for achieving a goal
the mechanism of government
3
: the processes involved in or responsible for a natural occurrence (as evolution or an action or reaction)
Medical Definition
mechanism
noun
mech·a·nism
ˈmek-ə-ˌniz-əm
1
: a piece of machinery
2
a
: a bodily process or function
the mechanism of healing
b
: the combination of mental processes by which a result is obtained
psychological mechanisms
3
: the fundamental physical or chemical processes involved in or responsible for an action, reaction, or other natural phenomenon
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