From Longman Dictionary of Contemporary Englishcrystal ballˌcrystal ˈball noun [countable] ROMa glass ball that you can look into, which some people believe can show what is going to happen in the future
Examples from the Corpus
crystal ball• Not glass to reflect bit of the world, but a crystal ball to look into soas to understand the world.• You are on a globe that looks like a crystal ball or a marble in a light bed of cotton wool.• A crystal ball in which one can call up the past?• They must not have hired him for his political foresight, either, because his crystal ball record is abysmal.• Gazing into our crystal ball, we see Scott breaking her campaign promise to not privatize Tucson Water.• The scientists' crystal ball is a bit cloudy on some things though.• Robbie remembered the crystal ball from his previous visit.• I feel stocks will move higher long term, but the next six months or year I leave to crystal ball gazers. 