Definition of sill :
1. A piece of timber across the bottom of a canal lock for the gates to shut against.
2. A young herring.
3. 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.
4. The floor of a gallery or passage in a mine.
5. The shaft or thill of a carriage.
6. The timber or stone at the foot of a door; the threshold.
7. The timber or stone on which a window frame stands; or, the lowest piece in a window frame.
bottom of the frame, ledge
beam (part of speech: noun)
- I lean upon the window sill, The trees and summer happy seem; Green, sunny green they shine, but still My heart goes far away to dream. - "Poems Chiefly From Manuscript", John Clare.
- Put the money on the window sill of your room. - "The Clue of the Twisted Candle", Edgar Wallace.
- " The window- sill had cut me right across here," she pointed to the space just below her nose. - "A Little Florida Lady", Dorothy C. Paine.