A pressure gauge shows build-up inside a system, read as stress or tension that is rising. Dream books take a needle near the limit as a sign of strain that wants release.
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.