A minus sign is read as subtraction — letting go, losing something, or a lack that is felt. It can also stand for the relief of taking something away that was too much.
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.