n. any nonverbal action or gesture that encodes a message
n. any incitement to action
n. an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes
s. notably out of the ordinary
n. 信号, 暗号, 近因, 导火线
vt. 向...作信号, 标志, 用信号通知
vi. 发信号
a. 作为信号的, 显著的
[计] 信号