Stardust is read as connection to something vast, the idea that we are made of the same matter as the stars. Dream books also link it to magic, glamour and fleeting enchantment.
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.