The proportion of a pot that a hand of a given strength will win, on average. Pot equity does not represent the number of bets invested -- stronger hands have more pot equity than weaker ones. Against three opponents, you need to win more than 25% of the time to come out ahead. If pot equity is greater than 25%, then you defend it and want to avoid being driven out by raises. Conversely, it often makes sense to try and push others out, so they sacrifice their pot equity. This is a different way of thinking about pot odds. One must not defend pot equity when the pot odds do not justify it.