Definition of ballast noun from the Oxford Advanced Learner's Dictionary



    BrE BrE//ˈbæləst//
    ; NAmE NAmE//ˈbæləst//
    [uncountable] Parts of boats and ships
    jump to other results
  1. 1heavy material placed in a ship or hot-air balloon to make it heavier and keep it steady See related entries: Parts of boats and ships
  2. 2a layer of stones that makes a strong base on which a road, railway/railroad, etc. can be built
  3. Word Originmid 16th cent.: probably of Low German or Scandinavian origin.
See the Oxford Advanced American Dictionary entry: ballast