downcut
down cut |ˈdounˌkət ˈdaʊnkət | ▶verb ( downcuts, downcutting, past and past participle downcut ) [ no obj. ] Geology (of a river ) erode downward through its bed.
down |cut ▶verb ( downcuts, downcutting, past and past participle downcut ) [ no obj. ] Geology (of a river ) erode downwards through its bed.