Events that have the same probability.
Example
In the random experiment that consists of rolling an honest die with six faces numbered 1 to 6 and recording the result that appears on the top face, the events: “A: rolling an even number” and “B: rolling an odd number” are equiprobable events, because: P(A) = \(\frac{1}{2}\) and P(B) = \(\frac{1}{2}\).