—n.
1 any heavy material placed in a ship or the car of a balloon etc. to secure stability.
2 coarse stone etc. used to form the bed of a railway track or road.
3 Electr. any device used to stabilize the current in a circuit.
4 anything that affords stability or permanence.
—v.tr.
1 provide with ballast.
2 afford stability or weight to.
Etymology: 16th c.: f. LG or Scand., of uncert. orig.
Useful english dictionary. 2012.