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

Consider using Cambria as window-sill cladding, shelving for a wet bar, or even as focal-point wall installations that serve as artwork in their own right. —Betsy Cribb Watson, Southern Living, 1 Mar. 2026

The car’s striking interior features racing seats upholstered in Poltrona Frau Heritage Castagno leather, which is also featured on the door sills and luggage straps. —Robert Ross, Robb Report, 23 Feb. 2026

For example, Hancock recommends this approach when your plants are positioned directly in a sunny south-facing sill. —Gemma Johnstone, The Spruce, 8 Feb. 2026

Even our teacher joined in, making a case for sill (herring), most famous in its inlagd (pickled) form. —Colton Valentine, New Yorker, 24 Jan. 2026

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