: any of the small timbers or metal beams ranged parallel from wall to wall in a structure to support a floor or ceiling

Illustration of joist

Illustration of joist
  • J joist

Examples of joist in a Sentence

Recent Examples on the Web Cantilevered decks using wood floor joists have a history of creating interior wood rot for the exact same reason. Tim Carter, Chicago Tribune, 15 Sep. 2023 Unlike more expensive options, this one comes complete, featuring a plywood floor with cedar floor joists, shingles, and hardware. Laura Kristine Miller, Better Homes & Gardens, 26 Sep. 2023 Spread the joists out farther too—ideally twenty-four inches. Time, 22 Aug. 2023 Twist a screw eye into the hole, tightening it fully into the joist. Hannah Bruneman, Better Homes & Gardens, 2 Aug. 2023 Left untreated, a swarm of termites can chew through the floor joists and roof rafters of a house, weakening your home from the inside, Alexander explains. Brittany Anas, House Beautiful, 27 July 2023 Next, drill through your home's rim joist, and run copper pipe and electrical cable through the hole and to the ground. Merle Henkenius, Popular Mechanics, 25 June 2021 In one squat, residents replaced all the rotting joists in their building, using materials lifted from construction sites. Dan Kois, Curbed, 16 Jan. 2023 Next, press the drywall up tight against the joist and secure it along the seam with drywall nails or screws driven into the center of the joist. Joseph Truini and Merle Henkenius, Popular Mechanics, 18 Aug. 2020 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'joist.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English giste, joiste, from Anglo-French giste, from Vulgar Latin *jacitum, from Latin jacēre to lie — more at adjacent

First Known Use

15th century, in the meaning defined above

Time Traveler
The first known use of joist was in the 15th century

Dictionary Entries Near joist

Cite this Entry

“Joist.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/joist. Accessed 1 Dec. 2023.

Kids Definition


: a small beam laid crosswise to support a floor or ceiling

More from Merriam-Webster on joist

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