(mathematics, astronomy) The mean plane occupied by the orbit of a satellite during a precession cycle; the plane normal to the orbital precession pole of the satellite.

to flatten, or make into a plane

the planet Mars

Of or pertaining to a plane. / Flat, two-dimensional. / (graph theory, of a graph) Able to be embedded in the plane with no edges intersecting.

(astronomy) a ring of dust, moonlets and other matter that orbits a planet (such as Saturn) as a flat disc; gaps in the ring are due to the presence of shepherd moons

In art, the imaginary plane correspondent with the physical surface of a drawing, painting or print.

A specialist in urban planning.

Any of the four gas giant planets in the Solar System: Jupiter, Uranus, Saturn, or Neptune.

A system of gears that has a central gear wheel (sun gear) around which others (planet gears) rotate, often within an outer ring.

(astronomy) Of, or relating to planets, or the orbital motion of planets. / Of, or relating to the Earth; terrestrial. / Of, or relating to the whole Earth; global. / (of a gear train) epicyclic