Definition of prior probability in English:

prior probability

noun

Statistics
  • A probability as assessed before making reference to certain relevant observations, especially subjectively or on the assumption that all possible outcomes be given the same probability.

    • ‘The probability is either a prior probability or a conditional probability.’
    • ‘To estimate the probability that a potential father is the father of an offspring we need to make assumptions regarding the prior probability of a potential father being the father.’
    • ‘Her lawyers demonstrated that the test did not take proper account of the prior probability and thus made a tacit initial assumption of guilt.’
    • ‘The resultant posterior probability then becomes a prior probability for the second drawing, the result of which is used to calculate a further posterior probability.’