A disk partition is a section of the hard drive that is separated from other segments.
Defines how a disks storage is allocated
A partition is the total disk space allocated to a single drive letter/volume and the local division of a Hard Disk.
Many drives come with a single partition already set up, but all storage devices are truested as a mass of unallocated space when there are no partitions.
You need a partition to be able to write to the drive