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

Lightly spray a microfiber cloth with the solution, then wipe down each sill. —Brandee Gruener, Southern Living, 22 Jan. 2026

Of them clogging the sills of our doors and windows with their downy scales. —Literary Hub, 21 Jan. 2026

All of the above procedures can be carried out on a sunny window sill. —Joshua Siskin, Oc Register, 9 Jan. 2026

The caseworker would walk through a house wearing white gloves, inspecting window sills and mantels for dust. —Stephanie Land, Time, 30 Oct. 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