A guide dog stands for trusted guidance through unfamiliar territory. Tradition reads it as loyalty and as willingness to rely on another when you cannot see the way yourself.
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.