SILL, noun [Latin solum; allied to solid. The primary sense is probably to lay, set or throw down.] 1. Properly, the basis of foundationof a thing; appropriately, a piece of timber on which a building rests; the lowest timber of any stucture; as the sills of a house, of a bridge, of a loom and the like. 2. The timber or stone at the foot of a door; the threshhold. 3. The timber or stone on which a window frame stands; or the lowest piece in a window frame. 4. The shaft or thill of a carriage. [Local.]
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI