someone who directs the performance of musicians or a piece of music

The conductor raised his baton. 指挥举起了指挥棒。

a guest conductor 嘉宾指挥

a railway official who travels on and is responsible for a train

someone whose job is to sell tickets on a bus, train, or other public vehicle

a substance that allows heat or electricity to go through it

Metal is a good conductor of heat. 金属是良好的热导体。