sill

noun

ˈsil 

1

: a horizontal piece (such as a timber) that forms the lowest member or one of the lowest members of a framework or supporting structure: such as

a

: the horizontal member at the base of a window

b

: the threshold of a door

2

: a tabular body of igneous rock injected while molten between sedimentary or volcanic beds or along foliation planes of metamorphic rocks

3

: a submerged ridge at relatively shallow depth separating the basins of two bodies of water

Examples of sill in a Sentence

Recent Examples on the Web

Up front, the grille is blacked out and there’s a new splitter, there are new sills along the side, and, in the back, the bumper and diffuser have been reworked. —Bryan Hood, Robb Report, 30 Apr. 2025

However, Boyett says the sill wears down over time, leading the Corps to rebuild the sill in the fall of 2024 to prevent another water scare in New Orleans. —Kati Weis, CBS News, 28 Apr. 2025

Upstairs, a mid-chiseled wooden boar and horse are left unfinished in Joel's workspace, a guitar leans against the bedroom window sill, and a copy of Idiot's Guide to Space lies half read on the nightstand. —EW.com, 21 Apr. 2025

Lintels above doors, and sills below windows, are made from stones imported from Mount Ventoux, located some 18 miles (30 kilometers) away. —Tom Mullen, Forbes.com, 20 Apr. 2025

Word History

Etymology

Middle English sille, from Old English syll; akin to Old High German swelli beam, threshold

First Known Use

before the 12th century, in the meaning defined at sense 1

Rhymes for sill

• bill
• brill
• chill
• drill
• fil
• fill
• frill
• gill
• grill
• grille
• jill
• kill

Kids Definition

sill

noun

ˈsil 

1

: a horizontal piece (as a timber) that forms the lowest part of a supporting structure: as

a

: the horizontal piece at the base of a window

b

: the timber or stone at the foot of a door : threshold

2

: a flat mass of igneous rock injected while melted between other rocks