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

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

(geology) A plane of separation between rock masses.

plural of scaleboard plane

A plane for cutting from a board a wide shaving forming a scaleboard.

(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.

plural of divisional plane

(finite geometry) The finite projective plane of order 2, having the smallest possible number of points and lines, 7 each, with 3 points on every line and 3 lines through every point.

(physics) A constant-frequency wave whose wavefronts are infinite parallel planes of constant peak-to-peak amplitude normal to the phase velocity vector.

plural of plane wave