(set theory) The Cartesian product of two real lines.

(engineering) A plane which serves as a reference or base for the measurement of other quantities.

(nautical) A technique for navigation using planar geometry. / (nautical, proscribed) A technique for navigation using the assumption the Earth is flat.

(anatomy) Any vertical plane that divides the body into anterior and posterior (belly and back) sections.

A general-purpose bench plane, used for general sizing of wood and for smoothing or straightening edges.

(geology) The planar surface between adjacent strata

(anatomy) Any plane that divides the body into superior and inferior parts, roughly perpendicular to spine.

(anatomy) Any plane that divides the body into superior and inferior parts, roughly perpendicular to spine.

(mathematics) Either half of an infinite plane (divided by a straight line)

Platanus × hispanica, a tree in the genus Platanus.