磁盘分区是使用分割编辑器（partition editor）在磁盘上划分几个逻辑部分，盘片一旦划分成数个分割（Partition），不同类的目录与文件可以保存进不同的分割。越多分割，也就有更多不同的地方，可以将文件的性质区分得更细，按照更为细分的性质，保存在不同的地方以管理文件；但太多分割就成了麻烦。空间管理、访问许可与目录搜索的方式，依属于安装在分割上的文件系统。当改变大小的能力依属于安装在分割上的文件系统时，需要谨慎地考虑分割的大小。

磁盘分区可做看作是逻辑卷管理前身的一项简单技术。

Disk partitioning or disk slicing is the creation of one or more regions on a hard disk or other secondary storage, so that an operating system can manage information in each region separately. Partitioning is typically the first step of preparing a newly manufactured disk, before any files or directories have been created. The disk stores the information about the partitions' locations and sizes in an area known as the partition table that the operating system reads before any other part of the disk. Each partition then appears in the operating system as a distinct "logical" disk that uses part of the actual disk. System administrators use a program called a partition editor to create, resize, delete, and manipulate the partitions.