A Partition, put simply, is a segment of a Hard Drive that is self-contained, and seperate from other portions of the drive.

Let's take an 80GB Hard Drive as an example. Usually, a Drive like this will actually have a Formatted Capacity of around 74GB

So, a Partition Table might look like this:

Partition Number File System Partition Size
Partition 1 FAT32 8GB
Partition 2 NTFS 20GB
Partition 3 Ext3 20GB
Partition 4 Ext2 20GB
Partition 5 FAT32 20GB