Family fruit trees
Family fruit trees consist of 2 or 3 different varieties grafted on to a single tree, so you can grow several varieties in a relatively small space.
More about Family fruit trees
Family fruit trees consist of 2 or 3 apple or pear varieties grafted on to the same stem - in effect you have a small orchard on a single tree.
The advantage of a family fruit tree is that the varieties are chosen to be compatible with each other in their blossom and fruiting seasons, and the tree takes up less space than growing the same varieties individually.