1. heavy material placed in a ship or aircraft to provide stability
Usage: nautical; aviation
2. crushed stone or gravel used as a foundation for railroad tracks
Usage: railroad
3. something that provides stability or steadiness
Usage: figurative

1. to provide with ballast for stability

Examples

• The ship carried water ballast in its lower compartments.
• Workers laid fresh ballast under the railroad tracks.
• The hot air balloon needed more ballast to descend safely.
• His calm presence served as ballast during the crisis.
• The crew ballasted the vessel before the storm.
• Granite ballast kept the train tracks level and stable.