frequentist

The frequency interpretation of probability is fairly self explanatory, in that it defines a probability as a limiting frequency. If we throw a (fair) die often enough, then we will eventually find that each number comes up about a sixth of the total time. The longer we continue to throw the die, the nearer the result will come to the ideal value of 1/6 for each number. The probability of an event is then defined by the relative frequency, as the throws continue to an idealized infinity.

One of the curious features of probability is that in everyday speech it is used in two rather different circumstances: first, when there is some essential randomness, and second, when our uncertainty is due to lack of knowledge.