Data about a piece of data. Examples include
- The FileAllocationTable of a FAT FileSystem
- describes the on-disk distribution of the data that makes up each file.
The journal in a Journalling FileSystem
- describes the actions to be taken upon the MetaData of a file in the FileSystem it resides on.
The control file in a Deb Package for DebianLinux
- specifies the content of the package and its relation to other packages.
Bibliographic records (such as per the MARC and DublinCore standards)
- contain information like the Title, Author, Date, etc of documents in a database in order to ease look-up.
APT and Yum repository headers
- Contains Information about the packages, and dependencies that it requires to install
The list is endless. Even this page you're reading is MetaData, it is a description of MetaData.