Ballast is any substance that is used in ships or hot-air balloons to make them heavier and more stable. Ballast usually consists of water, sand, or iron.
N-UNCOUNT
Ballast is any substance that is used in ships or hot-air balloons to make them heavier and more stable. Ballast usually consists of water, sand, or iron.
N-UNCOUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012