That's Cache-memory. Cash is something else...
The Level 2 cache memory is a small, fast memory close to the CPU core that stores data that's very frequently used.
Look at it this way:
The CPU needs some data. It first(if you don't count the L1 Cache) checks the L2 Cache if it's there. If not it goes to the RAM and checks there. And finally, if it's not there eighter it grabs it from the harddrive.
Simplified.