A choir is read as harmony, many voices blending into one sound. Dream books link it to belonging and cooperation, and to finding your place within a group.
Has this come up in your dreams before? What was going on in your life then?
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.