1
: a heavy substance (such as rocks or water) placed in such a way as to improve stability and control (as of the draft of a ship or the buoyancy of a balloon or submarine)
tossed several tons of ballast overboard
2
: something that gives stability (as in character or conduct)
She provided the ballast we needed during stressful times.
3
: gravel or broken stone laid in a railroad bed or used in making concrete
4
: a device used to provide the starting voltage or to stabilize the current in a circuit (as of a fluorescent lamp)
ballasted; ballasting; ballasts
1
: to steady or equip with or as if with ballast
They ballast the canoe with large rocks.
2
: to fill in (something, such as a railroad bed) with ballast (see ballast entry 1 sense 3)
Examples of ballast in a Sentence
Recent Examples on the Web
David Szondy, New Atlas, 27 Oct. 2024
Many invasive species have been introduced into the lakes through ballast water.
—Caitlin Looby, Journal Sentinel, 1 Oct. 2024
Cheri Lucas Rowlands, Longreads, 14 Oct. 2024
The crews will place ballast on the bridge’s two stationary ends to prevent possible structural movement caused by floodwater.
—Pioneer Press, Twin Cities, 20 June 2024
See all Example Sentences for ballast 
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Noun
Once towed into place, ballast tanks at one end flooded and FLIP, well, flipped.
—David Szondy, New Atlas, 27 Oct. 2024
Many invasive species have been introduced into the lakes through ballast water.
—Caitlin Looby, Journal Sentinel, 1 Oct. 2024
Verb
Often home is where the old people are—grandparents and porch-rocking neighbors who stayed put their whole lives, ballast to keep everyone else’s voyage stable.
—Cheri Lucas Rowlands, Longreads, 14 Oct. 2024
The crews will place ballast on the bridge’s two stationary ends to prevent possible structural movement caused by floodwater.
—Pioneer Press, Twin Cities, 20 June 2024
See all Example Sentences for ballast
Dictionary Entries Near ballast
Cite this Entry
“Ballast.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ballast. Accessed 22 Nov. 2024.
Copy CitationKids Definition
ballast
1 of 2 noun
bal·last
ˈbal-əst 
1
: heavy material used especially to make a ship steady or to control the rising of a balloon
2
: gravel or broken stone laid in a foundation for a railroad or used in making concrete
ballast
2 of 2 verb
: to provide with ballast
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