This usually means that the machine has got 5 controlled CNC-axes at the working spindle. If these are positioning axes, various processes like sawing and drilling can be carried out at any angle to the workpiece.
For free-shaped milling and thus, the milling of bodies with almost any shape, the 4th and 5th axis have to be interpolating axes.
Since 2006, special aggregates for tool changers are used, which allow 5-axis processing even though only 4 controllable axes exist. It is done with the 4th axis being either used for controlling the rotary motion or the tilting motion of the tool. Due to the system, one of these axes can of course be a positioning axis. Examples: Vario NC, Flex5