Tennis is a back-and-forth between two sides, so dream books read the court as a relationship or exchange where each move invites a reply. It also stands for rivalry and keeping score.
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.