A humidifier adds moisture to dry air, so dream books read it as softening and comfort. It can stand for bringing feeling back into a situation that has grown dry.
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.