| RUD | a sedimentary rock formed of coarse-grained material |
|---|---|
| RUD | fossil hominoids from north central Hungary |
| RUD | North American perennial herbs with showy cone-shaped flower heads |
| RUD | the state flower of Maryland |
| RUD | tall leafy plant with erect branches ending in large yellow flower heads with downward-arching rays |
| RUD | very tall branching herb with showy much-doubled yellow flower heads |
| RUD | the state flower of Maryland |
| RUD | European freshwater fish resembling the roach |
| RUD | (nautical) steering mechanism consisting of a hinged vertical plate mounted at the stern of a vessel |
| RUD | a hinged vertical airfoil mounted at the tail of an aircraft and used to make horizontal course changes |
| RUD | the vertical blade on a rudder |
| RUD | fish having the habit of following ships |