The clerical collar marks a person set apart for a calling. In dreams it is read as moral authority, a role that asks to be lived up to, or a voice of conscience you are hearing.
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.