inertia

noun in·er·tia \i-ˈnər-shə, -shē-ə\

: lack of movement or activity especially when movement or activity is wanted or needed

: a feeling of not having the energy or desire that is needed to move, change, etc.

physics : a property of matter by which something that is not moving remains still and something that is moving goes at the same speed and in the same direction until another thing or force affects it

Full Definition of INERTIA

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)

: indisposition to motion, exertion, or change : inertness

— in·er·tial \-shəl\ adjective

— in·er·tial·ly \-ˈnər-sh(ə-)lē\ adverb

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See inertia defined for kids

Origin of INERTIA

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

First Known Use: 1713

Related to INERTIA

Synonyms: idleness, indolence, laziness, shiftlessness, sloth

Antonyms: drive, industriousness, industry

Other Physics Terms

amplitude, centrifugal, centripetal, convection, gradient, hysteresis, kinetic, lase, quantum

INERTIA Defined for Kids

inertia

noun in·er·tia \i-ˈnər-shə\

Definition of INERTIA for Kids

: a property of matter by which it remains at rest or in motion in the same straight line unless acted upon by some external force

: a tendency not to move or change <He stayed at the job mostly because of his inertia.>

Medical Dictionary

inertia

noun in·er·tia \in-ˈər-shə, -shē-ə\

Medical Definition of INERTIA

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)

: lack of activity or movement—used especially of the uterus in labor when its contractions are weak or irregular