(optics) A surface to which rays reflected or refracted by another surface are tangents.

(of a missile) fired from the ground, or from a ship, at an aircraft in flight, or at an incoming missile

(of a missile) fired from an aircraft at a target on land or water

(geometry) A surface (in more than two dimensions, a plane is trivially developable) that can be flattened into a plane without distortion.

A numerical description of the flatness or roughness of a surface, especially an optical or machined surface.

Overland flow of excess water (with or without accumulated contaminants) that cannot be absorbed by the ground as infiltration.

(aeronautics) A moveable surface attached to a machine such as an aircraft or submarine that can be used to control the machine's motion in roll, pitch or yaw.

(mathematics) A one-dimensional complex manifold; a generalization of the complex plane.

(geography) Water collecting on the ground or in a stream, river, lake, sea or ocean, as opposed to groundwater.

(mathematics) A surface formed when a given curve is revolved around a given axis. If the resulting surface is a closed one, it also defines a solid of revolution.