n (1)信(暗)号(sign (eg a movement of the hand，a light，a sound)，esp one arranged beforehand，giving a command，warning or other messages)[C]：smoke～s 烟雾信号;a danger～危险信号;A red light/lamp/flag is often used as a～for (of) danger. 红灯/灯/旗常被用作危险的信号。 give the～to attack/advance 发出进攻/前进的信号;make a～with a red light 用红灯发出信号;raise one's hand as a～for the game to begin 举手示意比赛开始;〖同〗sign，indication;

(2)信号机(器，物)(machine，device or object，etc used for this purpose)[C]：a railway～铁路信号灯;traffic～s 交通信号灯;a～device 信号机;

(3)触发……的行动和事件(action or events that causes sth else to happen)[C][N (for)]：Her arrival was the～for the party to begin. 她的到达意味着宴会即将开始。 The strike was the～for revolt. 罢工是叛乱的导火线。

(4)(无线电等)信号(message，sound received or sent by a radio set，etc)[C]：pick up a radio～from the missing boat 捕捉到失踪船只的无线电信号;receive a～from a satellite 接收到卫星讯号;an area with a(n) poor/excellent TV～电视信号不良/极佳的地区;

v(1)发(打)信号(make a signal or signals)[I，I+prep (to) (for)]：Joan was～ling wildly. 琼在使劲地打着信号。 He was～ling urgently to me. 他在急切地向我打手势。 The ship～led for a pilot. 那条船发信号要求派引水员去。He～led to his soldiers for the attack to begin. 他向士兵们发出开始进攻的信号。

(2)用信号示意(警告)(make known of warn with or as if with signals)[T+n，T+n+prep (to)，T+that，T+wh-inf，D+n+prep (for/to)，D+n+that，D+to+n+that，D+n+wh，D+to+n+wh，C+n+to-inf，D+prep (to)+to-inf]： The bugler～led a retreat. 号兵吹号通知撤退。The sergeant～led an order.中士打手势发出命令。Both sides have～led their willingness to start negotiations. (fig)双方都表示出开始谈判的意愿。～a message to sb 向某人发消息;～(to sb) that one is about to turn left(向某人)发信号示意要左转弯;～(sb) which way Mary is going to 用信号告知(某人)玛丽要走哪条路;We～led a passing ship for help. 我们向一艘驶过的船发出了求救信号。The thief～led (his friend) that a policeman was coming. 那小偷(向他的同伙)示意警察来了。 The conductor～led the orchestra to rise.指挥示意乐队起立。The office～led his men to advance. 军官示意士兵们前进。〖同〗motion，gesture;

(3)标志着，表明(be a sign of)[T+n]：A period～s the end of a sentence. 句号表示一个句子的结束。

→′signaler n 信号员(兵);′signalman n 信号员(兵);′signal-box n 信号所(塔)