Sill

1. n. A young herring.
2. n. 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.
3. n. The timber or stone at the foot of a door; the threshold.
4. n. The timber or stone on which a window frame stands; or, the lowest piece in a window frame.
5. n. The floor of a gallery or passage in a mine.
6. n. A piece of timber across the bottom of a canal lock for the gates to shut against.
7. n. The shaft or thill of a carriage.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.