inertia ellipsoid

inertia ellipsoid

[i′nər·shə i′lip‚sȯid]
(mechanics)
An ellipsoid used in describing the motion of a rigid body; it is fixed in the body, and the distance from its center to its surface in any direction is inversely proportional to the square root of the moment of inertia about the corresponding axis. Also known as Poinsot ellipsoid.