beam¹/bim; biːm/ n [C] 1 a) a line of light shining from the sun, a lamp etc 光线,光束: The beam of the flashlight flickered and went out. 手电筒的光闪了一下就灭了。 b) a line of energy such as RADIATION or MICROWAVEs 〔辐射能、微波等的〕射束,射线 2 a long heavy piece of wood or metal used in building houses, bridges etc 〔建筑物的〕梁 3 a big happy smile 喜色,笑容