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

2

: 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

3

: 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

Examples 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

To appease Republicans concerned that the new provider tax mechanism would harm rural hospitals, Senate negotiators added a provision that would double funding for rural hospitals beginning in 2026 over a five-year period. —Sara Dorn, Forbes.com, 1 July 2025

Experts interviewed for this story generally agreed that although Kamb and Ganguli’s paper illuminates the mechanisms behind creativity in diffusion models, much remains mysterious. —Quanta Magazine, 30 June 2025

With only a simple majority required to advance the legislation, rather than the 60-votes needed to move forward with most legislation, Senate Democrats have few mechanisms to combat the bill's progress. —Kaia Hubbard june 29, CBS News, 29 June 2025

Do not submerge the sliding mechanism, Hensley warns. —Daley Quinn, Southern Living, 29 June 2025

Word History

First Known Use

1662, in the meaning defined at sense 1a

Phrases Containing mechanism

• defense mechanism
• escape mechanism
• survival mechanism

Rhymes for mechanism

• autism
• fascism
• racism
• sikhism
• statism
• sufism
• thomism
• tourism
• tropism
• abolitionism
• aldosteronism
• americanism

Kids 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

mechanistic

ˌmek-ə-ˈnis-tik 

adjective