crossbeam /ˈkrɒsˌbiːm/

• 1. 

  N-COUNT A crossbeam is a long, thick bar of wood, metal, or concrete that is placed between two walls or other structures, especially in order to support the roof of a building. (房顶的)横梁

  例：

  He hung the light from a steel crossbeam in the roof.

  他在屋顶上的钢横梁上吊上电灯。