A crescent moon is read as growth or gentle waning, depending on its direction, a phase in motion rather than a fixed state. In many cultures it is also a symbol of faith and of the feminine.
Does the traditional reading fit your dream, or did it mean something else to you?
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.