A trifecta and exacta are two types of BETS in horse racing. A trifecta bet is when a person BETS on the first three horses to finish in a race in the correct order. An exacta bet is when a person BETS on the first two horses to finish in a race in the correct order. Both of these BETS require the bettor to accurately predict the outcome of the race, making them more difficult and potentially more rewarding than other types of BETS.