A multiple bet consisting of two selections, both of which much win to gain a return.
The double is a bet where two selections are made and if the first wins everything that would have been returned is then used as stake for second. This style of bet is popular because it create the potential for larger returns but at the expense of increased risk as all it takes is one loosing selection for the bet to return nothing. Similar to the treble and accumulator the only difference being a lower number of selections. Each way and to-place only options are also available at some bookmakers.
A multiple bet consisting of three selections, all of which much win to gain a return.
The treble is a bet where three selections are made and the returns from the first are rolled over to the second, then the returns from the second rolled over to the third. Larger returns can be achieved using this bet at the expense of increased risk as all it takes is one loosing selection for the bet to return nothing. Similar to the accumulator and double, only varying in their number of selections, a double having 2 and an accumulator having 4 or more.