sill /sɪl/noun 8adjective 1forms 3 noun8 •A breast wall; window breast; horizontal brink which forms the base of a window.She looked out the window resting her elbows on the window sill. •A threshold; horizontal structural member of a building near ground level on a foundation or pilings, or lying on the ground, and bearing the upright portion of a frame; a sill plate. •A threshold or brink across the bottom of a canal lock for the gates to shut against. •(historical) The inner edge of the bottom of an embrasure. •A stratum of rock, especially an intrusive layer of igneous rock lying parallel to surrounding strata.Minor palingenetic magmas probably were generated at this time and intruded the mantling rocks in the form of small sills and apophyses […]. — 1980 •A raised area at the base of the nasal aperture in the skull. •(UK) A young herring. •The shaft or thill of a carriage. adjective1 •(slang, rare) Silly. formssills · more sill · most sill
