inertia

noun

in·​er·​tia i-ˈnər-shə How to pronounce inertia (audio)
-shē-ə
1
a
: a property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force
b
: an analogous property of other physical quantities (such as electricity)
2
: indisposition to motion, exertion, or change : inertness
inertial
i-ˈnər-shəl How to pronounce inertia (audio)
-shē-əl
adjective
inertially adverb

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Inertia is the inherent property of a body that makes it oppose any force that would cause a change in its motion. A body at rest and a body in motion both oppose forces that might cause acceleration. The inertia of a body can be measured by its mass, which governs its resistance to the action of a force, or by its moment of inertia about a specified axis, which measures its resistance to the action of a torque about the same axis.

Examples of inertia in a Sentence

He blames governmental inertia for the holdup. After 10 years in an unsatisfying job she overcame her inertia and went back to school.
Recent Examples on the Web But words have an inertia of their own; one stock phrase hooks on to another, forming a rhythmic chain that has a distinct mood and a clear subject—language itself. Masha Gessen, The New Yorker, 19 Jan. 2024 It's gotten way too tilted to a place that is run with its own inertia and not getting anything done. Brittany Carloni, The Indianapolis Star, 10 Jan. 2024 See all Example Sentences for inertia 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'inertia.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

New Latin, from Latin, lack of skill, from inert-, iners

First Known Use

1713, in the meaning defined at sense 1a

Time Traveler
The first known use of inertia was in 1713

Dictionary Entries Near inertia

Cite this Entry

“Inertia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/inertia. Accessed 28 Mar. 2024.

Kids Definition

inertia

noun
in·​er·​tia in-ˈər-shə How to pronounce inertia (audio)
-shē-ə
1
: a property of matter by which it remains at rest or in unchanging motion unless acted on by some external force
2
: a tendency not to move or change
inertial adjective

Medical Definition

inertia

noun
in·​er·​tia in-ˈər-shə, -shē-ə How to pronounce inertia (audio)
1
a
: a property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force
b
: an analogous property of other physical quantities (as electricity)
2
: lack of activity or movement
used especially of the uterus in labor when its contractions are weak or irregular

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