Any heavy substance, as stone, iron, etc., put into the hold to sink a vessel in the water to such a depth as to prevent capsizing.
- Heavy material that is placed in the hold of a ship or the gondola of a balloon to enhance stability.
- Coarse gravel or crushed rock laid to form a bed for roads or railroads.
- The gravel ingredient of concrete.
- Something that gives stability, especially in character.
- To stabilize or provide with ballast.
- To fill (a railroad bed) with or as if with ballast.