ballast
/ˈbæləst; `bæləst/ n
1 [U] heavy material placed in a ship's hold to keep it steady 压舱物, 压载物（船中用以保持平稳的）.
2 [U] sand or other material carried in a balloon, that can be thrown out to make the balloon go higher 气球所装载的沙子或其他物质（可将其抛掉以使气球升得更高）.
3 [U] stones, etc used to make a foundation for a railway, road, etc （铺筑铁路、公路等之路基所用的）石块, 道渣.
4 [C] device used for stabilizing current in an electric circuit 镇流器.
5 (idm 习语) in ballast (of a ship) carrying only ballast （指船）仅装有压舱物的. ballast, v [Tn, Tn.pr]
~ sth (with sth) supply sth with ballast 给某物装上压载物.