No two fingerprints match, so the symbol stands for identity and the traces you leave. Dreaming of being identified by one is linked to responsibility, or to a fear of being found out.
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.