(astronomy, celestial mechanics) An imaginary celestial body (corresponding to another, real, orbiting one) which orbits with constant speed along an auxiliary circle (a circle which shares a diameter with the major axis of the elliptical orbit of the corresponding real celestial body), such that its position coincides with the position of the corresponding, real celestial body when that body passes through periapsis.

Alternative form of planetree / (mathematics) An ordered tree, a type of graph, in which the child nodes of each vertex have a definite number assigned.

Synonym of planet-struck

(anatomy) The anatomical position of the human skull, based on a plane passing through the inferior margin of the left orbit and the upper margin of each ear canal or external auditory meatus.

A two-dimensional plane (or other surface) of weakness along which a crystal or other solid will break when under stress.

(archaic) Afflicted by the astrological influence of a planet; struck down with amazement or shock; panic-stricken.

(astronomy, planetology) a planetary-mass object which has either been ejected from its system or was never gravitationally bound to any star or other such object, and that therefore orbits the galaxy directly.

Alternative spelling of ice plant

(mathematics, engineering) The complex plane on which Laplace transforms are graphed; a mathematical domain where processes are viewed in the frequency domain rather than the time domain; used as a graphical analysis tool in engineering and physics.

(geology) A plane of separation between rock masses.