conductor
/kənˈdʌktə(r); kən`dʌktɚ/ n
1 person who directs the performance of an orchestra, a choir, etc (esp by standing in front of them and gesturing with his arms) （管弦乐队、 合唱团等的）指挥.
2
(a) (Brit) person who collects fares on a bus （公共汽车上的）收票员.
(b) (US) (Brit guard) person in charge of a train （火车上的）乘务员, 列车员（英式英语用guard）.
3 substance that conducts heat or electric current 导体（导热或导电的物质）
a `lightning conductor 避雷器
Wood is a poor conductor. 木头是不良导体.