Rebate is a top edge cut on the stone so that it does not allow the rainwater to penetrate inside the stone mortar or joint and flows quickly from the horizontal surface of stone masonry.
Throating is a groove provided inside the cornice, sill, and coping to prevent water flows with the wall surface and allows it to discharge away from the wall surface. It protects walls from the impact of rainwater.
Chases is a stones course provided at the top of the wall. It also protects from rainwater. It is generally constructed in an ornamental design.