Why does metadata matter?
Metadata is a term created by a Greek prefix "meta" and a Latin word "data." "Meta" means "after, behind or beyond" and "data" is factual information used for calculating, reasoning or measuring. Metadata means something behind or beyond data itself, and it includes data about its content, containers and contextual information.
A formal definition would be:
Metadata is data about data, data associated with an object, a document, or a dataset for purposes of description, administration, technical functionality and preservation.