Sill

Part of speech: noun (n.)

1. The basis or foundation of a thing; especially, a horizontal piece, as a timber, which forms the lower member of a frame, or supports a structure; as, the sills of a house, of a bridge, of a loom, and the like. Hence:

2. The timber or stone at the foot of a door; the threshold.

3. The timber or stone on which a window frame stands; or, the lowest piece in a window frame.

4. The floor of a gallery or passage in a mine.

5. A piece of timber across the bottom of a canal lock for the gates to shut against. Sill course (Arch.), a horizontal course of stone, terra cotta, or the like, built into a wall at the level of one or more window sills, these sills often forming part of it.

Part of speech: noun (n.)

The shaft or thill of a carriage. [Prov. Eng.]

Part of speech: noun (n.)

A young herring. [Eng.]