sill
1 Americannoun
-
a horizontal timber, block, or the like serving as a foundation of a wall, house, etc.
-
the horizontal piece or member beneath a window, door, or other opening.
-
Geology. a tabular body of intrusive igneous rock, ordinarily between beds of sedimentary rocks or layers of volcanic ejecta.
noun
noun
-
a shelf at the bottom of a window inside a room
-
a horizontal piece along the outside lower member of a window, that throws water clear of the wall below
-
the lower horizontal member of a window or door frame
-
a continuous horizontal member placed on top of a foundation wall in order to carry a timber framework
-
a flat usually horizontal mass of igneous rock, situated between two layers of older sedimentary rock, that was formed by an intrusion of magma
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
Earth Science - Middle School
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Earth Science - High School
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Rocks and Minerals - Middle School and High School
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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
![]()
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.