1. the horizontal piece at the bottom of a window or door frame
2. a horizontal timber or stone forming the bottom of a doorway
Usage: construction
3. a sheet of igneous rock intruded between existing rock layers
Usage: geology

Examples

• She placed the potted plant on the window sill.
• The cat likes to sit on the sill and watch birds outside.
• Water had collected on the bathroom window sill.
• He stepped carefully over the door sill.
• The old house had a marble sill at the entrance.
• The geologist identified a diabase sill in the rock formation.