Dream books read a lagoon as quiet, protected emotion — warmth and stillness cut off from the open sea. It can stand for comfort, and sometimes for keeping the wider world at a distance.
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.