Definition of sill in English:


Line breaks: sill
Pronunciation: /sɪl
(also chiefly Building cill)


1A shelf or slab of stone, wood, or metal at the foot of a window opening or doorway.
More example sentences
  • The designer suggested shortening window openings on one side of the kitchen, where sills were only 2 feet from the floor.
  • The library and its adjacent structure are detailed so that the viewer is gently aware of new sills and metal door frames and an illuminated linear storage unit.
  • This year the stone work lintels, sills and other features were restored and the general area around the church cleaned up.
1.1A strong horizontal beam forming a base in the frame of a timber-framed building.
More example sentences
  • Because Miller's family owns a sawmill, he agreed to take care of the sill plates, the truss material, and the rafters.
  • The sill beam is a horizontal beam which may be set in a foundation trench or placed directly on the ground surface.
1.2Each of the lower horizontal members of the frame of a cart or motor or rail vehicle.
More example sentences
  • Wide metal door sills and soft-blue ambient lighting welcome you into the car.
  • Built in 1988, it had doors that dropped down into the high sills, like the window glass in a standard door.
  • I've got substantial front-end damage - bumper, bonnet, cross-member and sill.
1.3 Geology A tabular sheet of igneous rock intruded between and parallel with the existing strata. Compare with dyke2.
More example sentences
  • Several igneous dikes and sills have been intruded into this sedimentary sequence, the largest of which is the Great Whin Sill, a quartz-orthopyroxene dolerite of late Carboniferous age.
  • Clastic dykes do not exclusively intrude sediments; they also intrude granitic rock and mafic sills and are associated with lava flows in volcanic environments.
  • Other leucogranite sheets are intruded as layer-parallel sills along the main foliation.
1.4An underwater ridge or rock ledge extending across the bed of a body of water.
More example sentences
  • Never be afraid to fish the turbulent, white water directly beneath the sill, for the water along the bottom may be quite calm in comparison to the surface.


Old English syll, sylle 'horizontal beam forming a foundation', of Germanic origin; related to German Schwelle 'threshold'.

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Word of the day retroflex
Pronunciation: ˈrɛtrə(ʊ)flɛks
turned backwards