The grail is the object of the greatest quest, so it stands for the deepest goal you are chasing. Dream books read finding it as fulfilment, and searching for it as longing for meaning.
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.