The term COMBO BET is a type of wager in horse racing. It is a combination of two bets, an EXACTA and a Boxed Quinella. An EXACTA is a bet on which two horses will finish first and second in a race in the exact order. It is a 6 letter word. A Boxed Quinella is a bet on which two horses will finish first and second in a race in any order. This type of bet gives the bettor more chances to win, as it allows them to pick two horses that can finish in either order.