parimutuel betting (păr´Ĭmyōō´tyōōĕl), system of cooperative wagering invented (c.1870) in France by Pierre Oller. According to the system, the holders of winning tickets divide the total amount of money bet on a race (the pool), after deductions for tax and racetrack expenses. The uniqueness of parimutuel betting lies in the fact that the gambling public itself determines the payoff odds (e.g., if many people have bet on the actual winner of a contest then the payoff will be low, simply because many winners will divide the pool). Parimutuel wagering is the accepted betting procedure at major horse-racing tracks throughout the world. Greyhound tracks and jai alai games also use the system. Considered a major deterrent to illegal bookmaking, the modern parimutuel system depends on high-speed electronic calculators, known as totalizators or tote boards, to record and display up-to-the-minute betting patterns.

par·i-mu·tu·el / ˌparə ˈmyoōchoōəl/ (also par·i·mu·tu·el) • n. [often as adj.] a form of betting in which those backing the first three places divide the losers' stakes (less the operator's commission): pari-mutuel betting. ∎  a booth for placing bets under such a system.