A sportsbook is a gambling establishment that accepts wagers on various sporting events. These establishments can either be retail locations that offer in-person betting or online/mobile platforms. They are also referred to as bookmakers.

These types of establishments typically accept bets on a variety of popular sports including American football, basketball, baseball, hockey, soccer, horse racing and greyhound racing. They may also offer other types of bets such as over/under totals and proposition bets.

In the United States, legal sportsbooks are operated by a number of companies, individuals and state governments. While most of these establishments are state-regulated, it’s still important to understand the rules of a particular sportsbook before placing your bet. This can help you make the best decision on where to place your bet and how much to wager.

To ensure their income, most sportsbooks profit from bettors who win by taking money from bettors who lose. This is a different model than a betting exchange, where players bet against each other and the house does not profit from winning bettors.

To compensate for the house edge, sportsbooks adjust their odds regularly. They do this by moving the handicaps on against-the-spread bets, adjusting the odds in moneyline bets and raising or lowering the odds in Over/Under totals and prop bets. For example, if Patrick Mahomes’ passing total was set at 249.5 yards and the sportsbook was seeing lots of action on the over, it would lower the over/under to -125 and raise the under to 252.5 to encourage more action on the under.