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

Wherever conspiracism is reshaping public life, two preventatives are vital: to defend the integrity of knowledge-producing institutions and bolster confidence in the ballast of common sense. N.c., The Economist, "Conspiracy theories are dangerous—here’s how to crush them," 12 Aug. 2019 But in 2019, Rodriguez has shed his past inconsistency and emerged as ballast for the Red Sox rotation, a pattern that continued with seven shutout innings in a 9-4 Red Sox victory over the Rays at Tropicana Field. Alex Speier,, "‘Steady Eddie’ Rodriguez gets Red Sox back on track," 23 July 2019 The Bear and its sister boat, the Bull, are both reproductions of an 1860s-era sandbagger sloop, a boat developed after watermen started racing shoal-draft sloops using sandbags instead of their catch of the day as ballast. Washington Post, "Take Someone Sailing Day gives newbie sailors nautical skills," 6 July 2019 Concrete is typically used as ballast to help intentionally sink ships -- those slated to become reefs -- straight down in an upright fashion and to hold them in place. Kevin Spear,, "Orlando utility donates 200 tons of concrete to help sink cocaine ship," 2 July 2019 Semi-submersibles have grown increasingly sophisticated over the years as drug traffickers have refined the basic design, reducing the ship’s profile with a variety of means, including ballast tanks designed to lower the ship in the water. Kyle Mizokami, Popular Mechanics, "Watch the Coast Guard Chase Down a Drug-Running Semi-Submersible," 12 July 2019 Ships have ballast tanks that are filled and emptied of water to stabilize the vessel. Andrea Leinfelder, Houston Chronicle, "Katy-based Envirocleanse moves forward with ballast water treatment system," 7 June 2019 Alexis Taylor croons in a high, understanding tremble, and Joe Goddard offers plummy, sad ballast. Spencer Kornhaber, The Atlantic, "Hot Chip Hones the Meaning of ‘Ecstasy’," 25 June 2019 The zebra mussel, which is native to Eastern Europe and Western Russia, made its way to Western Europe and the U.S. as a stowaway in ships' ballast water. Christina Nunez, National Geographic, "Invasive species, explained," 5 June 2019

Recent Examples on the Web: Verb

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 Seawater ballasts help with stability and the horizontal surface is layered in solar panels and bristles with antennas and a small wind generator. Bill Monroe,, "Local boat builder helps rower reach his ambition: Cross the Pacific Ocean," 5 Jan. 2018 Heritage-Crystal Clean contracted with Huston Electric to retrofit the light ballasts with LED fixtures. Carole Carlson, Post-Tribune, "Industry fines help fund upgrades at Gary schools," 23 Oct. 2017

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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Statistics for ballast

Last Updated

20 Aug 2019

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Time Traveler for ballast

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

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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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Comments on ballast

What made you want to look up ballast? Please tell us where you read or heard it (including the quote, if possible).


a haphazard or makeshift solution

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