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

Bedrooms Window sills, baseboards, ceiling fan blades, and all surfaces of the bedroom should be dusted. —Patricia Shannon, Southern Living, 9 Feb. 2025

In the Key of Ursa Minor Matthew Tierney Three fake plastic bushes per sill in the mall promenade. —Max Ufberg, hazlitt.net, 10 Jan. 2025

These narrow compartments house the HVAC vents and provide space to hang up a jacket, store shoes and sit on the door sill when taking off and putting on footwear. —New Atlas, 27 Dec. 2024

Indoor success requires a bright window sill and constant monitoring of the soil moisture levels. —Arricca Elin Sansone, Southern Living, 29 Jan. 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

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