inertia /in-ûrˈshi-ə, -shyə or -shə/ noun

1. Inertness
2. The inherent property of matter by which it continues, unless constrained, in its state of rest or uniform motion in a straight line

inerˈtial adjective

Of or relating to inertia

inertˈly adverb

inertˈness noun

inert gas noun

Any of a group of elements whose outer electron orbits are complete, rendering them inert to all the usual chemical reactions

inertial confinement noun

In fusion studies, short-term containment of plasma arising from inertial resistance to outward forces, achieved mainly by using a powerful laser

inertial control guidance or inertial control navigation noun

An automatic gyroscopic guidance system for aircraft, missiles, etc using data computed from acceleration and the physical properties of the earth, but dispensing with the magnetic compass and independent of ground-based radio aids

inertia-reel seat belt noun

A type of self-retracting seat belt in which the wearer is constrained only when violent deceleration of the vehicle causes the belt to lock

inertia selling noun

Sending unrequested goods to householders and attempting to charge for them if they are not returned