From entry Bayesian network in glossary Artificial Intelligence: humans at the heart of algorithms
A Bayesian network is a network of evidence and deriveed properties/facts linked by conditional probabilities that can be used to work out the probabilities of various facts given evidence. The same network can typically be used to make inferences in different directions, for example working out the probability of seeing someone with an umbrella if it is rainy, or the probability that it is rainy if you spot someone with an umbrella.
Also used in hcistats2e: Chap. 12: page 135