Learn in the textbookClassifying Data by Attribute and Structure
DefinitionMetadata (メタデータ) describes not the contents of data but its attributes, such as when it was created, who created it, and its format.
ExplanationIt is also called "data about data." Without opening the data itself, you can use metadata to find, classify, and manage the data you need. In a database, the definitions that set each field's name, type, and unit are also metadata.
AnalogyLike the classification label on a library book. You can find it on the shelf by title, author, and call number without reading a page.
Memory hook"Meta" comes from Greek and means "beyond" or "one level up." Metadata sits one level above the data and describes it.