n. 1 a person who directs the performance of an orchestra or choir etc. 2 (fem. conductress) a a person who collects fares in a bus etc. b US an official in charge of a train. 3 Physics a a thing that conducts or transmits heat or electricity, esp. regarded in terms of its capacity to do this (a poor conductor). b = lightning-conductor. 4 a guide or leader. 5 a manager or director. conductor rail a rail transmitting current to an electric train etc. conductorship n.
[ ME f. F conducteur f. L conductor (as conduct) ]