n. 信號(hào)，暗號(hào);預(yù)兆，征象;動(dòng)機(jī);導(dǎo)火線;
vt. 向…發(fā)信號(hào);用動(dòng)作（手勢(shì)）示意;以信號(hào)告知;
vi. 發(fā)信號(hào);
adj. 顯著的，優(yōu)越的;暗號(hào)的，作信號(hào)用的;
signal
n
1 sign, gesture, sound, etc that conveys a message, command, etc （傳遞信息、 命令等的）信號(hào), 手勢(shì), 聲音, 暗號(hào)
a signal made with a red flag 用紅旗打出的信號(hào)
hand signals, ie made by the driver of a car, etc to show which way it will turn, etc 手勢(shì)信號(hào)（司機(jī)指示轉(zhuǎn)彎等的）
She flashed the torch as a signal. 她用手電筒發(fā)信號(hào).
He raised his arm as a signal for us to stop. 他抬起手臂示意我們停下.
A red light is usually a signal for/of danger. 紅燈通常是危險(xiǎn)的信號(hào).
2 any device or object placed to give people a warning, information, etc （給人警告、 信息等的）信號(hào)器或信號(hào)物
traffic signals, ie for cars, etc in the streets 交通信號(hào)
The railway signal (ie light) was on red, so the train stopped. 鐵路紅燈亮了, 所以火車停下了.
3
(a) any event or action that causes some general activity 觸發(fā)某些普遍活動(dòng)的事情或行動(dòng)
The President's arrival was the signal for an outburst of cheering. 總統(tǒng)來(lái)到爆發(fā)一陣歡呼聲.
(b) anything indicating that sth exists or is likely to happen 表明某事物存在或可能發(fā)生的任何事物
Her speech yesterday was a signal that her views have changed. 她昨天的講話標(biāo)志著她的觀點(diǎn)已經(jīng)轉(zhuǎn)變.
Is this announcement the signal of better times ahead? 宣布的這件事是否預(yù)示往後日子越過越好了?
4 sequence of electronic impulses or radio waves transmitted or received （電子脈沖或無(wú)線電波的）信號(hào)
receive a signal from a satellite 接收到衛(wèi)星信號(hào)
an area with a poor/good TV signal 電視信號(hào)弱[強(qiáng)]的地區(qū)
[attrib 作定語(yǔ)]
signal strength 信號(hào)強(qiáng)度. signal, v (-ll-; US -l-) [I, Ipr, Tn, Tn.pr, Tf, Tw, Dn.pr, Dn.f, Dpr.f, Dn.w, Dpr.w, Dn.t, Dpr.t no passive 不用於被動(dòng)語(yǔ)態(tài)] ~ (to sb/sth) (for sth) make a signal or signals; send or express (sth) in this way; communicate with (sb) in this way 發(fā)信號(hào); 用信號(hào)傳達(dá)（某信息）; 用信號(hào)與（某人）通訊
He seems to be signalling. 他似乎正在發(fā)送信號(hào).
signal wildly with one's arms 奮力揮臂打信號(hào)
signal a message (to sb) 用信號(hào)（向某人）傳遞消息
(fig 比喻) signal one's discontent by refusing to vote 拒絕投票以示不滿
(fig 比喻) an event signalling a change in public opinion 說(shuō)明公眾輿論變化的事件
signal that one is going to turn/which way one is going to turn 打信號(hào)示意要轉(zhuǎn)彎[走哪條路]
signal (to) the commanding officer (that...) 向指揮官發(fā)信號(hào)（報(bào)告...）
signal to the regiment for the attack to begin 向團(tuán)部發(fā)出開始進(jìn)攻的信號(hào)
signal (to) sb which way to go 示意某人走哪條路
signal (to) the waiter to bring the menu 示意要服務(wù)員把菜單拿來(lái).
signal adj [attrib 作定語(yǔ)]
remarkably good or bad; outstanding （好或壞）顯著的; 出色的
a signal victory, success, failure, etc 極大的勝利、 成功、 失敗等.