Half a circle recalls a rising sun, an arch or people gathered in an arc around a speaker. It is read as something partly complete, or as an opening where the other half has yet to be found.
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.