tube /tju:b/ n. ［c］ 1.管，试管：test tube baby 试管婴儿；a tube of toothpaste 一管牙膏；a picture tube 显像管 2.地铁(BrE)：go by tube 乘地铁 3.电子管，显像管：There is something wrong  with the tubes in TV set. 电视显像管出毛病了。