(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.

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

(physics) the effect on the surface of a liquid that makes it behave as a stretched elastic membrane; it is caused by unbalanced intermolecular forces / (physics) a measure of this effect

(chemistry) A surface-active agent, or wetting agent, capable of reducing the surface tension of a liquid; typically organic compounds having a hydrophilic “head” and a hydrophobic “tail”.

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

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

(idiomatic) To barely begin; to see or do only a fraction of what is possible.

capable of lowering the surface tension of a liquid

(military) A ground-based anti-aircraft missile.

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