What is the Grail? For many the Grail or ‘Holy Grail’ symbolises ‘perfection’ or a ‘state of excellence’ and primarily in the spiritual and mystical sense. The symbol for the Grail is often a cup, chalice or vessel that one drinks from. The meaning is simple and clear; in the spiritual context, the cup symbolises one’s own sustenance or nourishment. Taking things to the highest level, the Grail really symbolises ’enlightenment’ and inner spiritual illumination – and there really is such an experience – an experience that has been behind the religious impulse of man throughout history.
http://www.book-of-thoth.com/article1598.html