'Signal' in the Bible

Now the appointed signal between the men of Israel and the men in ambush was that when they made a great cloud of smoke rise up out of the city

But when the signal began to rise out of the city in a column of smoke, the Benjaminites looked behind them; and behold, the whole of the city went up in smoke to heaven.

Flee for safety, ye children of Benjamin, out of the midst of Jerusalem, and blow the trumpet in Tekoa, and set up a signal in Beth-haccerem; for evil appeareth out of the north, and a great destruction.