noun
base slab; foundation slab
In construction, the thick concrete slab forming the bottom of a structure, such as a building's foundation or a bridge's footing.
この建物の底盤は厚さが2メートルある。
The base slab of this building is two meters thick.
noun
batholith
In geology, a large mass of intrusive igneous rock that formed deep underground.
この地域の花崗岩は巨大な底盤の一部だ。
The granite in this area is part of a huge batholith.