Sill

In geology, a sill is a tabular mass of igneous rock that has been intruded laterally between layers of older rock.

In architecture, a sill is the bottom edge of a window; in construction, it is the bottom horizontal member of a wall or building to which vertical members are attached.

The Sill River is a tributary to the Inn River, merging with it in Innsbruck, Tyrol, Austria.