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Definition of sill

sill

/sɪl/
sill
Plural:sills
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sill Lexical Profile

sill Game Scores & Validity

• noun

1

A horizontal piece of wood, stone, or metal forming the bottom of a window frame or doorway.

Example

"She arranged a row of small potted succulents along the sunny window sill."

2

A strong horizontal structural member, such as a beam or timber, serving as the lowest foundation element of a wall, house, or bridge.

Example

"The carpenters had to replace the rotted oak sill before they could begin framing the new exterior wall."

3

A tabular sheet of igneous rock intruded horizontally between and parallel with the existing strata of older rock.

Example

"The Whin Sill in northern England is a prominent geological formation composed of ancient dolerite."

Synonyms
View all synonyms for sill
Antonyms
View all antonyms for sill

• Rhymes for sill

• Nearby Words

silky
silky anteater
silky shark
sill
sillans falls
sillily
silliness

Word Origin & Etymology

From Old English 'syll' or 'sylle', meaning 'threshold, foundation, or beam', of Germanic origin; related to Middle Dutch 'sulle' and Old High German 'swelli'.

Usage Trend

Historical frequency of usage in published text.

180019102020
Data source: Google Books Ngram Viewer

Cite this Entry

Wordmom. (2026). Definition of Sill. In Wordmom Dictionary. Retrieved Nov 5, 2026, from https://wordmom.com/dictionary/sill
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