A hyper is what is actually on a single disk drive in the Symemtrix. A symmetrix volume is what is host presentable. So it sounds as though you have Raid-5 3+1. Raid 5 3+1 takes a Symmetrix volume slices it 4 ways and put those four slices on four different physical drives but they are presented as a single symmetrix volume.
Hyper is on the physical disk
symmetrix volume or symmvol is what is able to be presented to a host.