1
- a group of people or animals engaged in a task or activity for a fixed period of time and then replaced by a similar group接替或替换的一组人（或动物）：
the wagons were pulled by relays of horses
货车由一组接一组的马匹轮流拉
gangs of workers were sent in relays.
工人被分批轮流派出。
1.1
- usu. as modifier a race between teams of runners, each team member in turn covering part of the total distance接力赛：
a 550-metre relay race.
550米接力赛。
2
- an electrical device, typically incorporating an electromagnet, which is activated by a current or signal in one circuit to open or close another circuit继电器。
3
- a device to receive, reinforce, and retransmit a broadcast or programme（接收、加强并转播无线电或电视广播节目的）中继设备。
3.1
- a message or programme transmitted by such a device中继转播的信息（或节目）：
a relay of a performance live from the concert hall.
从音乐厅现场通过中继站实况转播的表演。
/亦读rɪˈleɪ/
with obj.
1- receive and pass on (information or a message)转达信息, 转告（消息）：
she intended to relay everything she had learned.
她打算把她知道的东西都传授出来。
1.1
- broadcast (something) by passing signals received from elsewhere through a transmitting station转播; 中继转发：
the speech was relayed live from the palace.
演讲从宫殿现场经过中继站实况转播。
词源
late Middle English (referring to the provision of fresh hounds on the track of a deer)： from Old French relai (noun), relayer (verb), based on Latin laxare 'slacken'.