The meaning of SILL is a horizontal piece (such as a timber) that forms the lowest member or one of the lowest members of a framework or supporting structure.

sill noun (ROCK LAYER) [ U ] earth science us / sɪl / a layer of rock that is created when hot melted rock forces itself into spaces between other rock, then cools and becomes solid …

Definition of sill noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

A sill is a shelf along the bottom edge of a window, either inside or outside a building.

Oct 31, 2025 · sill (plural sills) (architecture, also "window sill") A breast wall; window breast; horizontal brink which forms the base of a window.

sill (sɪl) n. 1. a horizontal piece or member beneath a window, door, or other opening.

sill, n.¹ meanings, etymology, pronunciation and more in the Oxford English Dictionary