Definition of "distress signal" []

• An international signal used by a distressed ship or aircraft to request help, as by radio broadcasts, flags, or flares. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Cressy’s distress signal was picked up by Tyrwhitt at 7: 07 a.m."
• "Newton Beech's distress signal — reported by the Graf Spee as having been weak — does not appear to have been picked up by any other British ship, and the Admiralty remained in ignorance of the fact that shortly after dawn that morning the position of the Graf Spee was 9° 20 'south, 6° 19' west."