LEARNit Dictionary
ballast
noun
/ˈbæləst/
UK
/ˈbæləst/
US
1
heavy material placed in a ship or hot-air balloon to make it heavier and keep it steady
وزنه تعادل, بالاست, سنگ بار
2
a layer of stones that makes a strong base on which a road, railway, etc. can be built
سنگ زیرسازی, بستر سنگی