A slingshot stands for the small one taking aim at the big one, as in the old story of David. Tradition reads it as stored tension released toward a target.
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.