(astronomy) The orbital plane passing through a planetary system's barycenter (center of mass) perpendicular to its angular momentum vector.

plural of ecliptic plane

plural of equatorial plane

A mirror with a flat surface (i.e. the surface is a single plane)

An aircraft used for surveillance.

plural of spotter plane

(differential geometry) Given a point P on a surface M, the tangent plane of M at point P, denoted by T_P(M), is the plane passing through P which contains the tangent lines of all the curves on M passing through P.

(aircraft, military) A military aircraft primarily designed to attack enemy aircraft. Frequently shortened to fighter.

(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.

A plane which declines from the zenith, or inclines toward the horizon.