in·er·tia Audio Help /ɪnˈɜrʃə, ɪˈnɜr-/ Pronunciation Key - Show Spelled Pronunciation[in-ur-shuh, i-nur-] Pronunciation Key - Show IPA Pronunciation
–noun 1. inertness, esp. with regard to effort, motion, action, and the like; inactivity; sluggishness.
2. Physics. a. the property of matter by which it retains its state of rest or its velocity along a straight line so long as it is not acted upon by an external force.
b. an analogous property of a force: electric inertia.