bal·​last | \ ˈba-ləst How to pronounce ballast (audio) \

Definition of ballast

 (Entry 1 of 2)

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)
in ballast
of a ship : having only ballast for a load


ballasted; ballasting; ballasts

Definition of ballast (Entry 2 of 2)

transitive verb

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: Noun The company said that high-capacity pumps would begin to pump water from the vessel's ballast tanks. Vivian Yee New York Times, Star Tribune, "Big container ship stuck in Suez Canal is 'a very big problem'," 27 Mar. 2021 However the finances do rely on bigger longer-term decisions, particularly whether a superstar trade emerges in the summer with Wiggins’ salary as the ballast. Patrick Murray, Forbes, "Should The Golden State Warriors Target Aaron Gordon At The NBA Trade Deadline?," 21 Mar. 2021 Crews were unable to reach equipment to stop the flooding in time, and the ballast tanks failed to work properly. Kyle Mizokami, Popular Mechanics, "Why Did the USS Thresher Sink? New Declassified Documents Reveal the Truth," 17 Mar. 2021 The Wake makes a predictably small wave compared with the splash of a six-figure boat with ballast tanks. Eric Tingwall, Car and Driver, "Yamaha WaveRunners and Sea-Doo Wake Ride the Wave," 17 Mar. 2021 Ian Oviatt said the ship lacked enough water in its ballast tanks, used to add weight at the bottom of a vessel, to offset that of the vehicles in the cargo decks above. Russ Bynum, Star Tribune, "Crews remove 3rd giant chunk of shipwreck off Georgia coast," 16 Mar. 2021 Originating from Eurasia, these mussels were first introduced in the 1990s when ballast water was emptied into the Great Lakes. Sarah Bowman, The Indianapolis Star, "Here are 5 of the most harmful invasive animals and insects wreaking havoc in Indiana," 15 Mar. 2021 So that leaves a limited selection, even if Meyers Leonard’s salary is utilized as cap-matching ballast. Ira Winderman,, "ASK IRA: Why should Heat want LaMarcus Aldridge if Spurs don’t?," 12 Mar. 2021 They were found in the Great Lakes in the late 1980s, likely having traveled over in freighter ballast tanks. Laura Schulte, Milwaukee Journal Sentinel, "Make sure to check your moss balls: Invasive zebra mussels hitch a ride to Wisconsin inside popular aquarium plant," 10 Mar. 2021 Recent Examples on the Web: Verb The species, which grows to 6 feet long and weighs up to 220 pounds, was prized for its swim bladder, or maw, an organ that helps ballast the animal. Adam Elder, Wired, "How a Pudgy Porpoise May Save Other Animals From Extinction," 16 Apr. 2020 Amid that debate, the role of the editorial board is to provide Times readers with a long-range view formed not by one person’s expertise and experience but ballasted by certain institutional values that have evolved across more than 150 years. New York Times, "What Is an Editorial Board?," 13 Jan. 2020 Some of that freshness comes from the cast, a cornucopia of effervescent young talent ballasted by a handful of doughty old-timers. New York Times, "‘Little Women’ Review: This Movie Is Big," 23 Dec. 2019 Gillis said the new bridge will be ballasted, rather than fixed. Mary Wisniewski,, "Metra awarded $17.8 million in federal funds to rebuild Irving Park rail bridge," 21 Aug. 2019 Green Bay’s unbalanced and condensed formations, presnap motions, first-down play-actions and intertwined route combinations play to Rodger’s sharp football IQ, ballasting his reads and timing. Andy Benoit,, "Aaron Rodgers, Packers’ Offense Primed to Thrive Under New Head Coach Matt LaFleur," 23 July 2019 Roughly a third of the structure is submerged and ballasted by 5,000 tons of iron ore. Michael J. Coren, Quartz, "Floating wind farms just became a serious business," 22 June 2019 The subs are built from a variety of materials, but primarily plastics, carbon fiber, and other composites, with a few metal components and some weights to ballast the vessel. Jay Bennett, Popular Mechanics, "The Preposterous World of Human-Powered Submarine Racing," 9 Aug. 2017 Seawater ballasts help with stability and the horizontal surface is layered in solar panels and antennas. Bill Monroe,, "Oregon tag holders asked/required to report hunting, fishing results," 11 Jan. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ballast.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of ballast


15th century, in the meaning defined at sense 1


1538, in the meaning defined at sense 1

History and Etymology for ballast

Noun and Verb

probably from Low German, of Scandinavian origin; akin to Danish & Swedish barlast ballast; perhaps akin to Old English bær bare & to Old English hlæst load, hladan to load — more at lade

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Time Traveler for ballast

Time Traveler

The first known use of ballast was in the 15th century

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Statistics for ballast

Last Updated

8 Apr 2021

Cite this Entry

“Ballast.” Dictionary, Merriam-Webster, Accessed 10 Apr. 2021.

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More Definitions for ballast



English Language Learners Definition of ballast

: heavy material (such as rocks or water) that is put on a ship to make it steady or on a balloon to control its height in the air


bal·​last | \ ˈba-ləst How to pronounce ballast (audio) \

Kids Definition of ballast

1 : heavy material used 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

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