Ballast

1. (a.) 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.
2. (a.) Any heavy matter put into the car of a balloon to give it steadiness.
3. (a.) Gravel, broken stone, etc., laid in the bed of a railroad to make it firm and solid.
4. (a.) The larger solids, as broken stone or gravel, used in making concrete.
5. (a.) Fig.: That which gives, or helps to maintain, uprightness, steadiness, and security.
6. (v. t.) To steady, as a vessel, by putting heavy substances in the hold.
7. (v. t.) To fill in, as the bed of a railroad, with gravel, stone, etc., in order to make it firm and solid.
8. (v. t.) To keep steady; to steady, morally.