The ones to your sides are called walls.
The one above your head is the roof.
Below your feet is the floor. Simple enough so far.
The plane in front of you is the face.
And behind you is the back.
Now, imagine a flat table top at waist height, this is called the table.
The high table is a parallel plane at shoulder height.
And the low table is at knee height.
Likewise, all other left/right naming is dependant on which hand the nunchaku are in. If your nunchaku are in your right hand, your right hip, right knee are your near hip, near knee and everything left is far hip, far knee, etc.
Parallel with the walls and the core is a plane that runs between your arm and your body, through your armpit. This is the cavity. Like the walls, depending which hand you've got your nunchaku in you have a near cavity and a far cavity.