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

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

Analysts note that as capital expenditure for AI and cloud infrastructure expands, corporate funding mechanisms are shifting. — CNBC, 28 Aug. 2026

Additionally, despite the Department of Justice’s lawsuit, Connecticut already has a mechanism in place for residents without status. — Derek Slap, Hartford Courant, 28 Aug. 2026

Stunt coordinator Joel Kramer rigged up a support mechanism for the 750-pound motorcycle, since otherwise the jump was deemed too dangerous. — ArsTechnica, 28 Aug. 2026

The same mechanism processes lithium for reactor coolants and breeding blankets. — Aman Tripathi, Interesting Engineering, 28 Aug. 2026

Word History

Etymology

probably borrowed from New Latin mechanismus, from Greek mēchanḗ "device, contrivance, siege engine" + New Latin -ismus -ism — more at machine entry 1

First Known Use

1662, in the meaning defined at sense 1a

Phrases Containing mechanism

• coping mechanism
• defense mechanism
• escape mechanism
• survival mechanism

Rhymes for mechanism

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

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