LUN
Logical Unit Number. A block-level volume that can be presented as a disk to any client device or server connected to the SAN.
Example: 24 600 GB spindles were configured as a RAID 5 Volume (Parity: n-1) with the overall capacity of 13.8 TB, and then presented to 3 ESXi Hosts as 4 LUN’s, each with a capacity of approximately 3.45 TB