The average result of a bet if you could place it infinitely many times.
Expected value is the long-run average profit or loss of a bet, weighting each outcome by its probability. A +EV (positive expected value) bet makes money on average; a -EV bet loses.
You don't need every bet to win — you need to consistently place +EV bets. Over enough repetitions, positive expected value turns into real profit, and negative expected value into real loss.
