1 a person who stands in front of an orchestra and directs the musicians （乐团的）指挥

2 (Brit 英) a person whose job is to collect money from passengers on a bus or to check their tickets （公共汽车的）售票员，收费员

3 (US 美) =GUARD¹(5)

4 a substance that allows heat or electricity to pass through or along it （导热或导电的）导体，传导体 ☞Compare semiconductor. 与semiconductor比较。