message in a bottle

message in a bottle (plural messages in a bottle or messages in bottles)

1. A message written on a scrap of paper, rolled up and put in an empty bottle and set adrift on the ocean; traditionally, a method used by castaways to advertise their distress to the outside world.
   • 1979, Sting (lyrics and music), “Message in a Bottle”, in Reggatta de Blanc, performed by The Police:

     I'll send an SOS to the world / I hope that someone gets my / Message in a bottle

2. (figurative) An analogous message sent off into the world or universe without knowledge of who the recipient will be: plaques on craft launched into outer space, interstellar radio messages, stationary time capsules, balloon mail, and so on.
   • 2021, Taylor Swift, Max Martin, Shellback (lyrics and music), “Message in a Bottle”, in Red (Taylor's Version)‎, performed by Taylor Swift:

     'Cause you could be the one that I love, oh, oh, oh / I could be the one that you dream of, of, of / A message in a bottle is all I can do-oo / Standin' here, hopin' it gets to you