In architecture, a starling (or sterling) is a defensive bulwark, usually built with pilings or bricks, surrounding the supports (or piers) of a bridge or similar construction. Starlings may be shaped to ease the flow of the water around the bridge, reducing the damage caused by erosion or collisions with flood-borne debris. They may also form an important part of the structure of the bridge, spreading the weight of the piers.
The term cutwater is used for such a structure shaped with water flow in mind, as a pier or starling with a diamond point.[1] A starkwater is a bulwark against ice floes.
Depending on their shape and location, some starlings may accumulate river debris, mud and other objects, potentially creating navigational hazards or hindering downstream water flow.