A twin is read as a double — another version of yourself, or two sides of one personality. Dream books link twins to balance, inner conflict and the question of who you are apart from others.
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.