(mathematics) the locus of points in the Euclidean plane that satisfies some geometric or algebraic definition; a curve in a plane (as opposed to higher-dimensional space)

(mathematics) Two-dimensional Euclidean space.

(mathematics) a representation of the space of complex numbers

(parapsychology, Theosophy) A supernatural plane of existence, propounded by esoteric philosophies, some religious teachings, and New Age thought.

(geometry) An angle formed by two intersecting straight lines.

(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.

An aircraft that flies alongside another, to advise or photograph it while experimental flights are being carried out.

plural of rabbet plane

(astronomy) The surface (plane) that contains the orbit of a planet in a solar system.

(astronomy) The surface (plane) that contains an orbit.