Definition of inertia in English:


Line breaks: in¦er|tia
Pronunciation: /ɪˈnəːʃə


[mass noun]
  • 2 Physics A property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force: the power required to overcome friction and the inertia of the moving parts See also moment of inertia.
    More example sentences
    • A better way to measure the mass of a microscopic sample is to quantify the sample's inertia as it is forced into motion.
    • Unlike Galileo, Newton insisted that the law of inertia applied only to motion in a straight line, not circular motion.
    • How fast and in what order remains to be seen, but the direction is a matter of inertia without friction.
  • 2.1 [with modifier] Resistance to change in some other physical property: the thermal inertia of the oceans will delay the full rise in temperature for a few decades
    More example sentences
    • The relatively large mass and thermal inertia of female desert tortoises usually prevents winter activity but facilitates their relaxed homeostasis.
    • Soil for the grass over the common room adds to the thermal inertia of the whole.
    • A heavy body weight is a disincentive for movement and physical activity, creating ‘movement inertia.’



More example sentences
  • The doors close as soon as Jewel is clear, and the inertialess transport quickly jets away from the building, circling around the city center and out over the desert.
  • The mirror surface of the ball doubles as a solar collector, and everything, the radio control, the laser, targeting, gyros, inertialess drive, all run off the battery.
  • A simple inertialess quasi-real-time microwave holographic recording system is described and preliminary results are presented.


early 18th century (in sense 2): from Latin, from iners, inert- (see inert).

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