noun: (often pluralized) A method of long-distance communication sometimes used in ancient and undeveloped societies, consisting of messages conveyed by means of columns or intermittent puffs of smoke.
noun: A message or sign sent by this method.
noun: (idiomatic, often pluralized) An indirect message or indication, especially concerning a future event.
noun: A type of flare or combustion device sometimes used as a distress signal.
