1.A sign made for the purpose of giving notice to a person of some occurence, command, or danger; also, a sign, event, or watchword, which has been agreed upon as the occasion of concerted action. "All obeyed The wonted signal and superior voice Of this great potentate."
2.A token; an indication; a foreshadowing; a sign; anything taken as evidence of some process. "The weary sun... Gives signal of a goodly day to-morrow." "There was not the least signal of the calamity to be seen."
3.Hence: (Electronics) A measureable electrical quantity, such as voltage or current, that conveys information by varying in magnitude over time; as, the signals from the strongest commercial radio stations can be received over hundreds of miles.
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