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)

see also in ballast

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)

Examples of ballast in a Sentence

Recent Examples on the Web

Noun

In addition to underwater hull preservation work, the company’s Southern California shipyard also will recondition the ship’s superstructure, interior fuel and ballast tanks, and refurbish crew living spaces. —Prabhat Ranjan Mishra, Interesting Engineering, 25 Jan. 2026

Have bricks or river rocks concealed out of sight and ready to use as ballasts to hold the cloth in place against winds. —Neil Sperry, Fort Worth Star-Telegram, 22 Jan. 2026

Verb

The new 14-track collection ballasts her familiar dreamy, coquettish sound with vulnerability and anguish. —Nicole Fell, HollywoodReporter, 22 Aug. 2025

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

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