Sill

noun
1.
a horizontal timber, block, or the like serving as a foundation of a wall, house, etc.
2.
the horizontal piece or member beneath a window, door, or other opening.
3.
Geology. a tabular body of intrusive igneous rock, ordinarily between beds of sedimentary rocks or layers of volcanic ejecta.
noun
1.
Mount, a mountain in E central California, in the Sierra Nevada Mountains. 14,153 feet (4314 meters).
noun
1.
a shelf at the bottom of a window inside a room
2.
a horizontal piece along the outside lower member of a window, that throws water clear of the wall below
3.
the lower horizontal member of a window or door frame
4.
a continuous horizontal member placed on top of a foundation wall in order to carry a timber framework
5.
a flat usually horizontal mass of igneous rock, situated between two layers of older sedimentary rock, that was formed by an intrusion of magma
sill
(sĭl)
A sheet of igneous rock intruded between layers of older rock. See illustration at batholith.