Sill, n.

n. [A-S. syl, syll, Sw. syll, Dan. syld, I. Ger. sülle, sull, O. H. Ger. suelli, M. H. Ger. swelle, N. H. Ger. schwelle, probably from Goth. suljan, gasuljan, to lay a foundation, to found.]

1. The basis or foundation of a thing: as, the sills of a house, of a bridge, of a loom, and the like; hence, (a.) The timber or stone at the foot of a door: the threshold. (b.) The timber or stone on which a window-frame stands; or the lowest piece in a window-frame.
2. The shaft or thill of a carriage. [Prov. Eng.]
3. The young of a herring. [Prov. Eng.]