[xìn hào]
signal; semaphore; gun
an audible signal
音頻[響]信號
semaphore
臂板信號{鐵道}
light signal
燈光信號
identification signal
識別信號
distress signal; SOS
遇難信號{航海}
hash
雜亂信號{無}
A train must not pass a signal that is at danger.
火車切不可越過危險信號。
Signals are made with flags or lamps.
信號是用旗或燈發出的。