A bird striking glass is read as a sudden obstacle or a surprise that stops momentum. Folk tradition took it as a sign; dream readings today see it as an unseen barrier coming into view.
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.