Suppose you have a fair coin. Then tossing it has two possible outcomes: heads and tails. These are equally likely.
One of these possibilities must occur (assuming that the coin doesn't land on its side)
Before you flip the coin, these possibilities are undecided. If you flip the coin without looking at the result, then the outcome is decided, but which of the two possibilities has occurred is still unknown.
Thus one type of possibility is present or decided, while another is future or undecided.
The result of the coin toss is also such that exactly one outcome must be the case. In other words, one of the outcomes must occur (assuming the coin doesn't land on its side), but both of them cannot occur. It can therefore be said that the possibilities are dichotomous.
Is there a Latin word or phrase meaning decided dichotomous possibility (such as the result of a coin toss before you look at it)?