Douglas Harper's Etymology Dictionary
Wiktionary
n. 1 (context horse racing English) Any betting system in which all bets of a particular type are placed together in a pool; taxes and a house take are removed, and payoff odds are calculated by sharing the pool among all placed bets. (from 19th c.) 2 A booth used to place such bets, or a machine used to record bets and calculate payoffs. (from 19th c.)
Usage examples of "pari-mutuel".
Lights still flickered on the pari-mutuel, changing the odds: races in America tended to start when the punters had finished, not to any rigid clock.
He lost his license for giving stimulants to a horse--which he says she did--and later, without bothering to divorce him, she married a Southern California used-car dealer who was pretty well-to-do, or was until she got her scoop into his bankroll and started heaving it into the pari-mutuel windows at Santa Anita and Hollywood Park.
One bid and no offerings did not constitute a transaction according to the electronic definitions of the New York Stock Exchange pari-mutuel machine.
She had the morals of a vacuum cleaner and the soul of a pari-mutuel machine, a good figure, and that lovely vicious face, and she only stayed with Roger long enough to get ready for her first good step upwards in life.