Dream books read a stop sign as an inner call to pause before going further. It often appears when part of you senses that a situation needs a second look.
Has this come up in your dreams before? What was going on in your life then?
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.