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  • sill
    sill
    noun
    a horizontal timber, block, or the like serving as a foundation of a wall, house, etc.
  • Sill
    Sill
    noun
    Mount, a mountain in E central California, in the Sierra Nevada Mountains. 14,153 feet (4,314 meters).
Synonyms

sill

1 American  
[sil] / sɪl /

noun

  1. a horizontal timber, block, or the like serving as a foundation of a wall, house, etc.

  2. the horizontal piece or member beneath a window, door, or other opening.

  3. Geology. a tabular body of intrusive igneous rock, ordinarily between beds of sedimentary rocks or layers of volcanic ejecta.


Sill 2 American  
[sil] / sɪl /

noun

  1. Mount, a mountain in E central California, in the Sierra Nevada Mountains. 14,153 feet (4,314 meters).


sill British  
/ sɪl /

noun

  1. a shelf at the bottom of a window inside a room

  2. a horizontal piece along the outside lower member of a window, that throws water clear of the wall below

  3. the lower horizontal member of a window or door frame

  4. a continuous horizontal member placed on top of a foundation wall in order to carry a timber framework

  5. a flat usually horizontal mass of igneous rock, situated between two layers of older sedimentary rock, that was formed by an intrusion of magma

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

sill Scientific  
/ sĭl /
  1. A sheet of igneous rock intruded between layers of older rock.

  2. See illustration at batholith


Other Word Forms

Etymology

Origin of sill

before 900; Middle English sille, Old English syl, sylle; cognate with Low German süll, Old Norse syll; akin to German Schwelle sill

Vocabulary lists containing sill

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Sill, Emanuel concludes: “With none of the flags pointing to elevated systemic risks, EVR ISI Strategy continues to see S&P 500 ending 2026 at 7,750, with the potential for a bubble forming at 30%.”

From MarketWatch • Dec. 29, 2025

In the mountains east of San Diego, a wind gust of 102 mph was recorded at Sill Hill, nearing the all-time record of 105 mph recorded there on Feb. 26, 2020, Tardy said.

From Los Angeles Times • Jan. 22, 2025

Sill says people always reach out with funny questions about what exactly they can store.

From Seattle Times • May 17, 2024

Meanwhile, tributes have been left in memory of the tree in a dedicated room at The Sill: National Landscape Discovery Centre in Northumberland.

From BBC • Oct. 8, 2023

Known as Wally, she was a flight instructor at Fort Sill, an army base in southwestern Oklahoma, when she picked up the Life magazine featuring Jerrie Cobb.

From "Women in Space" by Karen Bush Gibson