Quiniela is a way to bet on the first two wins in a game. For example, in gamblers betting on a Jai-Alai might tell the casino the two participants they favor to win.
If no order is specified in the bet, then the bet is a Quiniela. If an order is specified, then the bet is a Perfecta. Obviously, the pay-off for the latter is greater.
A Spanish word which literarlly means "sports bet," the first recorded usage of Quiniela was in 1905.