The conditional probability of an event \(B\) in relationship to an event \(A\) is the probability that event \(B\) occurs after event \(A\) has already occurred. The notation for conditional probability is 

\[P(B|A)\]

This notation does not mean that \(B\) is divided by \(A\); rather, it means the probability that event \(B\) occurs given that event \(A\) has already occurred.