The banshee’s keening is read as grief given a voice — mourning for something that is ending. It is a symbol of sorrow and transition, not a notice of anyone’s death.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.