[GotaFancy?]

There are 2 ways to win a hand in poker. One way is to showdown with the best hand. The other way is for everyone to fold.

The only way everyone will fold is if you bet. Your "fold equity" is the chance that your opponent will fold if you bet.

If someone goes all in, then you have no fold equity. You can call, but it will go to showdown and you must have the best hand.
If someone is pot committed, then you have no fold equity - you know that regardless of the bet you make, your opponent will call you, with any 2 cards. Again you must showdown the best hand.
To have fold equity you must place a big enough bet that your opponent has a decision to make on whether to call (or raise) or fold.

Fold equity is the reason that aggression is so important in poker - you have 2 ways to win a pot, whilst passive players can only win the pot by having the best hand.