Information about a resource, such as the name of the author, the title of a document, the date of creation, and so on. The Compass Server robot uses metainformation as well as document contents when creating resource description

Information about information. Metainformation may include descriptive information about the size, format, or other characteristics of a client request, server response, or a document being transferred.

In the HTTP, information about the contents of the entity body, sent in entity header fields.