1. The act of scudding; a driving along; a rushing with precipitation.
2. Loose, vapory clouds driven swiftly by the wind. Borne on the scud of the sea. (Longfellow) The scud was flying fast above us, throwing a veil over the moon. (Sir S. Baker)
3. A slight, sudden shower.
4. (Science: ornithology) A small flight of larks, or other birds, less than a flock.
5. (Science: zoology) Any swimming amphipod crustacean. Storm scud. See the note under Cloud.