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

Dozens of house plants decorate the shelves and window sills, absorbing the light from windows that run from the tops of bookshelves to the ceiling. —Sarah D. Wire, USA Today, 29 July 2025

Meanwhile, a parrot in Northern Ireland has an unlikely best friend: A cat who often jumps up on the window sill, where the parrot likes to chat with him. —Thomas Westerholm, MSNBC Newsweek, 21 July 2025

The aluminum door sill guards are also black, as is the illuminated Porsche logo in the back. —Erik Shilling, Robb Report, 16 July 2025

Wet another clean microfiber cloth with your vinegar spray and wipe down the window frame and sills. —Ashlyn Needham, Southern Living, 12 July 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