partition table
also: partition map, MBR, GPT, disklabel
A data structure on a disk that describes how the disk's storage space is divided into logical sections (partitions). It tells the system where each partition starts, ends, and what type of data it contains.
A partition table is metadata stored at the beginning of a disk that maps out its divisions. It acts as a blueprint, defining the boundaries and properties of each partition so the operating system knows how to organize and access the disk.
There are two main formats: MBR (Master Boot Record), the older standard supporting up to 4 primary partitions and 2 TB disks, and GPT (GUID Partition Table), the modern standard supporting many more partitions and larger disks.
For example, a 500 GB disk might have a partition table describing a 100 GB Linux root partition, a 50 GB swap partition, and a 350 GB home partition. Tools like fdisk, parted, and gdisk let you view and modify partition tables.