The ratio of the expected player loss to the initial amount bet. For example if the house edge for blackjack is 0.5% then for every $100 you bet initially you can expect to lose 50 cents. The house edge is a good measure of expected player wins or losses over time but is not a perfect measure of comparing one game to another. The reason is the house edge does not include additional money bet (for example doubling in blackjack or raising in Three Card Poker) as money bet. Two common mistakes in calculating the house edge are not including ties (they should be counted towards money bet) and including additional money bet (like doubling and raising) towards money bet. An exception to the usual definition is in craps, in particular proposition bets that can take multiple rolls to resolve. For place, buy, lay, and hard way bets the house edge is defined as the expected player loss per bet resolved. Another exception is in Let it Ride, in which the house edge is the ratio of the expected loss to a single bet (or 1/3 of the total initial bet).
Also known as PC (percent casino). The percent of all wagers the house can expect to win, over a period of time. Can vary widely, but normally is about 30%.