1. 接力比赛(如赛跑或游泳)
    A relay or a relay race is a race between two or more teams, for example teams of runners or swimmers. Each member of the team runs or swims one section of the race.

    e.g. Britain's prospects of beating the United States in the relay looked poor.
           英国要在接力赛中战胜美国，前景看上去并不那么乐观。

2. 转播，传送，传输(电视或收音机信号)
    To relay television or radio signals means to send them or broadcast them.

    e.g. The satellite will be used mainly to relay television programmes...
           这颗人造卫星主要用途是转播电视节目。
    e.g. This system continuously monitors levels of radiation and relays the information to a central computer...
           这个系统不间断地监控辐射水平，并将信息传送到中央计算机。

3. (接受和发送电视或广播信号的)转播设备，中继设备
    A relay is a piece of equipment that receives television or radio signals from one place and sends them to another place.

relay

    e.g. ...a security system with satellite relays.
           带有卫星传输设备的保安系统
    e.g. ...a television relay station.
           电视转播站

4. 传（话）；转述
    If you relay something that has been said to you, you repeat it to another person.

    e.g. She relayed the message, then frowned...
           她把消息带到了，然后皱紧了眉头。
    e.g. The decision will be relayed to Iraq's ambassador at the UN.
           这个决定将会被传达给伊拉克驻联合国大使。