I. noun
also cill ˈsil
( -s )
Etymology: Middle English sille, selle, from Old English syll; akin to Old High German swelli beam, threshold, Old Norse svill, syll sill, Greek selis crossbeam, rower's bench, selma deck, rower's bench
1.
a. : a horizontal piece (as a timber) that forms the lowest member or one of the lowest members of a framework or supporting structure (as of a house, a bridge, a loom, a mine set, or a truck body) — compare mudsill
b. : the horizontal member or structure (as of wood, stone, or brick) at the base of a window opening serving especially to cover the wall at the base of the opening : windowsill
c. : the timber or stone at the foot of a door : threshold
d. : a piece of timber across the bottom of an entrance to a dock or a canal lock for the gates to shut against
e.
(1) : the inner lower edge of an embrasure of a fortification
(2) : one of the horizontal timbers forming the upper and lower boundaries of a gun port (as on an old warship)
2. : the floor of a coal seam
3. : a tabular body of igneous rock injected while molten between sedimentary or volcanic beds or along foliation planes of metamorphic rocks
4. : an elevation (as a low ridge between mountains) separating two valleys or basins ; especially : a submerged ridge at relatively shallow depth separating the basins of two bodies of water
5. : the top surface of a usually low or normally submerged dam
II. transitive verb
( -ed/-ing/-s )
: to provide with a sill
III. noun
( -s )
Etymology: by alteration
archaic : thill