noun
ballast
BAL-uhst
noun
1
Heavy material carried in a ship, balloon, or vehicle to provide stability.
"The old ship carried stone ballast in its hold to keep it steady at sea."
2
Crushed stone or gravel laid down to form a stable bed for a road or railway track.
"Workers spread fresh ballast along the section of track before laying new sleepers."
verb
1
To stabilise something by loading it with heavy material.
"The crew ballasted the vessel before setting out into rough water."
How to Use Ballast
Learner’s notesIn plain EnglishHeavy material used to keep something steady, whether a ship, balloon, or railway bed.
Common pairings
ballast tank
railway ballast
Word Forms
ballasted past tense, ballasts plural, ballasts singular
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The old ship carried stone _____ in its hold to keep it steady at sea.
Etymology
From Middle English, combining words meaning "bare" and "load."