A secret society is read as hidden knowledge and exclusive belonging. Dream books link it to curiosity about what goes on behind closed doors, or to feeling shut out of an inner circle.
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.