ballast

1 of 2

noun

bal·​last ˈba-ləst 

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)

ballast

2 of 2

verb

ballasted; ballasting; ballasts

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)

Phrases

in ballast

of a ship : having only ballast for a load

Examples of ballast in a Sentence

Recent Examples on the Web

Noun

State officials say the mussels can hide in ballast tanks, live wells, and engine systems, surviving long trips and posing risks to even remote mountain lakes. —Daniel Hunt, Sacbee.com, 27 Mar. 2025

The maritime archaeologist identified shell impact holes in the upper starboard of the hull’s ballast tank and significant battle damage to the base of the submarine’s conning tower. —Sean Kingsley, Smithsonian Magazine, 18 Feb. 2025

Verb

The oldest rail tunnel in the world, a London Tube section dating from 1863, was completely renovated — including the complex task of changing the old-fashion ballasted track to modern direct rail fixation — using this repair-in-place approach. —New York Daily News Editorial Board, New York Daily News, 28 Apr. 2025

That’s how much ballast the new Range Rover has tossed out, illustrating the automotive trend toward lightweighting. —Lawrence Ulrich, IEEE Spectrum, 29 Mar. 2013

Word History

Etymology

Noun

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

Verb

derivative of ballast entry 1

First Known Use

Noun

15th century, in the meaning defined at sense 1

Verb

1538, in the meaning defined at sense 1

Phrases Containing ballast

• in ballast

Rhymes for ballast

• calloused
• callused
• dialysed
• medallist
• paralysed

Kids 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