sill

/sɪl/

/sɪl/

Definitions of sill

1. noun

   structural member consisting of a continuous horizontal timber forming the lowest member of a framework or supporting structure
   types:

   doorsill, doorstep, threshold

   the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway

   windowsill

   the sill of a window; the horizontal member at the bottom of the window frame

   type of:

   structural member

   support that is a constituent part of any structure or building
2. noun

   (geology) a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock
   type of:

   rock, stone

   a lump or mass of hard consolidated mineral matter