Meaning of Bayes' theorem

Bayes'' the'orem

Pronunciation: (bāz, bā'ziz), [key]
— Statistics. Statistics.
  1. a theorem describing how the conditional probability of each of a set of possible causes, given an observed outcome, can be computed from knowledge of the probability of each cause and of the conditional probability of the outcome, given each cause.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.