A volume is a term in data compression for a file that has been compressed and split into different parts.
There are two advantages in having a compression utility with the ability for compression into volumes. First, it allows an individual to download the file in segments at his or her own pace. As well if there is a corruption only one volume is affected instead of the whole—which can be corrected using parity files. Second, it allows compression to a volume size compatible with removable media. For example, compressing a backup into 700MB chunks for easy storage on CD-Rs.