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in·er·tia

(ĭ-nûrshə)

1. Physics The tendency of a body at rest to remain at rest or of a body in straight line motion to stay in motion in a straight line unless acted on by an outside force; the resistance of a body to changes in momentum.

2. Resistance or disinclination to motion, action, or change: an entrenched bureaucracy's inertia.

[Latin, idleness, from iners, inert-, inert; see INERT.]

in·ertial adj.

in·ertial·ly adv.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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