An Etymological Dictionary of Astronomy and Astrophysics

Mechanics: For a rotating rigid body not subject to external torque, the closed curve described on the → inertia ellipsoid by the intersection with this ellipsoid of an axis parallel to the angular velocity vector and through the center.
Astro.: The path described by the North pole of the Earth in a reference frame attached to the Earth. The rotation axis of our planet is not fixed with respect to the Earth’s crust. It describes a motion within a square with an amplitude reaching 20 m.

Etymology (EN): Polhode, from Fr. polhodie, coined by Louis Poinsot (1777-1859), a French mathematician and physicist, the inventor of geometrical mechanics, from → pole + Gk. hodos “way.”

Etymology (PE): Qotbrâh, from gotb, → pole, + râh
“way, path” (from Mid.Pers. râh, râs “way, street,” also rah, ras “chariot;” from Proto-Iranian *rāθa-; cf. Av. raθa- “chariot;” Skt. rátha- “car, chariot,” rathyā- “road;” L. rota “wheel,” rotare “to revolve, roll;” Lith. ratas “wheel;” O.H.G. rad; Ger. Rad; Du. rad;
O.Ir. roth; PIE *roto- “to run, to turn, to roll”).