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 …—
Franklin D. Roosevelt
Franklin 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
In short, the mechanism used to provide partial state funding for homeschool and private-school students is now paying for those students to attend soccer camps, horseback riding classes, gymnastics and jiu-jitsu classes.
—Dp Opinion, Denver Post, 25 Apr. 2026
But critics of this effort say this internal mechanism fails to provide meaningful accountability and would protect wrongdoers from any future state bar investigation.
—Jaclyn Diaz, NPR, 25 Apr. 2026
This strongly suggests that a key mechanism for rapid quenching is a galaxy simply running out of its star-forming fuel.
—Paul Sutter, Space.com, 25 Apr. 2026
The Space Force made 20 individual awards the 12 companies in late 2025 and early 2026 using an acquisition mechanism known as Other Transaction Authority, or OTA, agreements.
—Stephen Clark, ArsTechnica, 25 Apr. 2026
See All Example Sentences for mechanism
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Dp Opinion, Denver Post, 25 Apr. 2026
But critics of this effort say this internal mechanism fails to provide meaningful accountability and would protect wrongdoers from any future state bar investigation.
—Jaclyn Diaz, NPR, 25 Apr. 2026
This strongly suggests that a key mechanism for rapid quenching is a galaxy simply running out of its star-forming fuel.
—Paul Sutter, Space.com, 25 Apr. 2026
The Space Force made 20 individual awards the 12 companies in late 2025 and early 2026 using an acquisition mechanism known as Other Transaction Authority, or OTA, agreements.
—Stephen Clark, ArsTechnica, 25 Apr. 2026
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 Apr. 2026.
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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