A globe of glass or crystal used to foretell the future.
The psychic looked into the crystal ball and saw into the future.
(by extension, used mostly in the negative form) A way of seeing into the future.
If her past is a crystal ball to her future, she will perhaps never be rich, even though she is a good, kind, educated, hard-working person.
One of the magickal tools of Wicca, used for divination and altar purposes