Hidden partitions refer to sections of a storage device, like a hard drive or SSD, that are not visible to the operating system or the user. These partitions can be used for various purposes, such as recovery tools or system backups, and are often created by manufacturers to help restore the device to its original state. These partitions are typically not assigned a drive letter and do not appear in file explorers. Users may need specialized software to access or manage hidden partitions, which can be crucial for troubleshooting or restoring a system when issues arise.