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

Seal gaps around doors, window sills, and where utility lines enter the house. —Arricca Elin Sansone, Southern Living, 30 June 2025

Also, keep your window sills clear of items that could prevent your curtains from fully blocking out the light. —Sophia Beams, Better Homes & Gardens, 25 June 2025

Police later found a silver revolver loaded with five bullets on the window sill, with its barrel pushed through the partially open window, according to the report. —Justin Muszynski, Hartford Courant, 14 May 2025

One photo shared by CBS News Pittsburgh showed a shattered window, any showed claw marks by a different window sill. —Angel Saunders, People.com, 7 June 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