sills

Noun

sill (plural sills)

1. (also "window sill") 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.
2. 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.
3. 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, Geological Survey Professional Paper, Volume 1119, U.S. Government Printing Office
4. A threshold or brink across the bottom of a canal lock for the gates to shut against.
5. A raised area at the base of the nasal aperture in the skull.
   • the nasal sill
6. (historical) The inner edge of the bottom of an embrasure.

See all 10 meanings of sill