A kettle builds heat until it whistles, so dream books read it as pressure rising, feelings coming to the boil, or simply the start of a calming ritual.
Where in your waking life have you met something like this lately?
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.