You know how a squirrel collects nuts to eat during the winter? Basically, you are the squirrel and superannuation are your nuts, and in this depressing metaphor, the winter is your retirement until you die.
Superannuation (or super) was designed by the Federal Government to ensure that all employees are saving a portion of their income to live on when retired. This portion is saved in a Superannuation fund, which builds up over time. You generally cannot touch these funds for any other reason than for use in retirement.
The Government has set a retirement age (currently 65) when superannuation can be accessed.