A windmill turns what blows past into useful work, so tradition reads it as resourcefulness and harnessing change. Tilting at windmills adds the image of battles with imagined enemies.
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.