What is an expected outcome in probability?

The expected outcome is the sum of (each possible occurrence times the probability of that occurrence).

For example, the expected outcome of rolling one die is:

1 * 1/6 + 2 * 1/6 + 3 * 1/6 + 4 * 1/6 + 5 * 1/6 + 6 * 1/6 = 3.5.