a characterization or description documenting the identification, management, nature, use, or location of information resources (data)
Metadata is commonly defined as “data about data.” Metadata is frequently used to locate or manage information resources by abstracting or classifying those resources or by capturing information not inherent in the resource. Typically metadata is organized into distinct categories and relies on conventions to establish the values for each category. For example, administrative metadata may include the date and source of acquisition, disposal date, and disposal method. Descriptive metadata may include information about the content and form of the materials. Preservation metadata may record activities to protect or extend the life of the resource, such as reformatting. Structural metadata may indicate the interrelationships between discrete information resources, such as page numbers.
In terms of archives, MARC format and EAD are standards for structuring descriptive metadata about collections. Dublin Core is a standard for structuring metadata that is intended for describing web resources.
In terms of information technology, metadata includes the documentation of data architecture, properties, and methods necessary to store, retrieve, and use the data in a meaningful manner. To the extent that data is a record, it may also include administrative, descriptive, preservation, and structural information.
Bergeron 2002, 9Metadata includes descriptive summaries and high-level categorization of data and information. Knowledge is information that is organized, synthesized, or summarized to enhance comprehension, awareness, or understanding. That is, knowledge is a combination and an awareness of the context in which the data can be successfully applied. Although the concept of data is roughly equivalent to metadata, unlike data, information, or metadata, knowledge implies a human—rather than computer—host.
Lynch 2000, 34We have an object and a collection of assertions about it. The assertions may be internal, as in a claim of authorship or date and place of publication on the title page of a book, or external, represented in metadata that accompany the object, perhaps provided by third parties. We want to ask questions about the integrity of the object: Has the object been changed since its creation, and, if so, has this altered the fundamental essence of the object? (This can include asking these questions about accompanying assertions, either embedded in the object or embodied in accompanying metadata).
ARLISNA 1999Having heard someone once define information science as “librarianship practiced by men,” Mr. Gorman concluded by defining metadata as “cataloging practiced by ill-informed men.”
Puglia, Reed, and Rhodes 2004, 6Metadata makes possible several key functions—the identification, management, access, use, and preservation of a digital resource—and is therefore directly associated with most of the steps in a digital imaging project workflow: file naming, capture, processing, quality control, production tracking, search and retrieval design, storage, and long-term management.