Even-Money Bet
Any wager that pays winnings equal to the stake (1:1), so a winning bet returns your stake plus the same amount again.
Definition
An even-money (or 'evens') bet pays 1:1: risk one unit to win one unit. Common examples are roulette's red/black, odd/even and high/low, the Pass Line in craps, Big/Small in Sic Bo, and the main hands in blackjack and baccarat. A 1:1 payout can feel like a fair coin flip, but the true probability of winning is always set slightly below 50% (for example, the zero pockets in roulette), which is precisely how the house edge is embedded. In blackjack, 'even money' also refers to a specific offer: taking a guaranteed 1:1 payout on your own blackjack when the dealer shows an ace, which is mathematically identical to taking insurance and is generally not advised.
Worked example
You bet $10 on red in European roulette and win, receiving your $10 back plus $10 in winnings. It looks like a 50/50 proposition, but red covers only 18 of 37 pockets; the single green zero is what turns a fair-looking even-money bet into a 2.70% edge for the house.
Why it matters
For learners, even-money bets are the clearest place to see that a 1:1 payout is not the same as a 50% chance. For professionals, explaining this gap is central to describing games honestly and to debunking the idea that even-money bets are 'safe'.