A double bet is where a punter makes two unrelated selections, and combines them together into one bet. In general terms, a double bet is the most simple form of multi bet also sometimes referred to as a parlay or accumulator.
When you place a double result bet, you are betting on two outcomes in one match with one stake. A double bet is a single betting option that combines the score of a game at half-time and the score at the end of the game. Assuming the half-time bet wins, the stake is then carried over to the second bet.