sill
nounUK /sɪl/
US /sɪl/
The flat piece of wood or stone at the bottom of a window.
She put a small plant on the window sill.
OTHER MEANINGS
2. The heavy piece of wood at the bottom of a door frame.
He tripped over the door sill as he walked in.
3. A horizontal piece of timber that supports the base of a building or wall.
The builders laid the sill before raising the walls.
4. The bottom part of a car's door opening.
Mud had collected along the door sill.