Metadata and metadata standards are intellectual constructs created to improve the ability to discover, access, and reuse research data that has been preserved or archived.
Metadata is simply data that describes other data. In other words it provides information about the content of a specific item. For example, an ebook's metadata could include information on what is the title, who is the author, where and when it was published, as well as a brief summary of the book itself. It also includes information on versioning, archiving, and other technical information for file, rights, and preservation management.
Metadata standards represent "the organization of metadata as a blueprint for how such data is structured" and can be described as a "container for metadata elements." These type of standards "establish a common understanding of the meaning or semantics of data, to ensure correct and proper use and interpretation of data."