Glass is clear yet fragile, so dream books read it as transparency, honesty and the sense that something precious could crack. Walking on glass is seen as moving carefully through a delicate situation.
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.