Definitions of metadata on the Web:

• Data that is used to describe other data. Data definitions are sometimes referred to as metadata. Examples of metadata include schema, table, index, view and column definitions.
  www.orafaq.com/glossary/faqglosm.htm
• Metadata is information about a particular data set which may describe, for example, how, when, and by whom it was received, created, accessed, and/or modified and how it is formatted. Some metadata, such as file dates and sizes, can easily be seen by users; other metadata can be hidden or embedded and unavailable to computer users who are not technically adept. Metadata is generally not reproduced in full form when a document is printed. ...
  www.krollontrack.com/legalresources/glossary.asp
• Informational data about the data, included in a signal's data stream.
  www.cdtv.ca/en/glossary.htm
• data about data. Metadata describes how and when and by whom a particular set of data was collected, and how the data is formatted. Metadata is essential for understanding information stored in data warehouses and has become increasingly important in XML-based Web applications.
  www.electronicscriptorium.com/glossary.html
• Data about data, or information known about the image in order to provide access to the image. Usually includes information about the intellectual content of the image, digital representation data, and security or rights management information.
  www.cdpheritage.org/resource/introduction/rsrc_glossary.html
• "data about data" describe the content, quality, condition, and other characteristics of data. Metadata is vital in helping potential users to find needed data and determine whether a data set will meet their needs before they spend the time and money to obtain and process it. This information will often include some of the following:
  web2.gov.mb.ca/mli/glossary/m_z.html
• Data about data. Index-type information pertaining to the entire data set rather than the objects within the data set. Metadata usually includes the date, source, map projection, scale, resolution, accuracy, and reliability of the information, as well as data about the format and structure of the data set.
  atlas.library.arizona.edu/glossaryk_p.htm
• Data about data. Includes information describing aspects of actual data items, such as name, format, content, and the control of or over data.
  dli.grainger.uiuc.edu/glossary.htm
• structured data about data, which may include information about the author, title and subject of web resources. Metadata is added in the section of the webpage or is stored in a database. It is available for searching but is not displayed on the page.
  members.optusnet.com.au/~webindexing/Webbook2Ed/glossary.htm
• Data about other data, commonly divided into descriptive metadata such as bibliographic information, structural metadata about formats and structures, and administrative metadata, which is used to manage information.
  www.cs.cornell.edu/wya/DigLib/MS1999/glossary.html
• Summary information regarding other information being presented. Metadata can describe any type of information resource and service, users can gain access to information about resources that are not available on-line for full text searching including: electronic documents, databases, collections of printed books, microforms, government information services, etc. Terms used for the subject field in the Newsroom must be referenced from the Government of Canada Core Subject Thesaurus.
  commnet.gc.ca/news_nouvelles/glossary_e.html
• (1) Information about a data set which is provided by the data supplier or the generating algorithm and which provides a description of the content, format, and utility of the data set. Metadata provide criteria which may be used to select data for a particular scientific investigation. (2) Information describing a data set, including data user guide, descriptions of the data set in directories, and inventories, and any additional information required to define the relationships among these. ...
  podaac.jpl.nasa.gov/glossary/
• Data which describes other data. For example, a description of a database in terms of its structure and the relationship between the entities in it. (www.oxford reference.com) Open Access Digital works that are made available often at no cost to the reader on the public Internet for purposes of education and research. (US Association of Research Libraries: www.arl.org)
  www.bl.uk/about/strategic/glossary.html
• information describing the characteristics of data. Data or information about data. Descriptive information about an organization’s data, data activities, systems, and holdings.
  www.sedris.org/glossary.htm
• Data (information) about data. Term which describes the data.
  web.mit.edu/warehouse/glossary.html
• means any additional or bibliographic information about one or more of the data collections, as notified to the End User from time to time. Metadata may be supplied by electronic means.
  edina.ac.uk/ukborders/terms.shtml
• the reference information about how the data is collected
  www.estuaries.gov/glossary.html
• Data about data. Metadata in HGL refers to documentation that describes the data layers themselves. All metadata in HGL adheres to the Federal Geographic Data Committee Content Standard for Geospatial Metadata.
  peters.hul.harvard.edu:8080/HGL/html/Help/glossary.htm
• Metadata is a description or definition of electronic data, or data about data. Often, metadata can only be accessed in certain viewing modes. Metadata can include descriptive HTML tags (see Meta Tag) and information about when a document was created, and what changes have been made on that document.
  practice.findlaw.com/glossary.html
• Information about data set. Metadata for geographical data may include the source of the data; its creation date and format; its projection, scale, resolution, and accuracy; and its reliability with regards to some standard. See data dictionary.
  www.richlandmaps.com/training/glossary/m_p.html
• Data that describe a dataset to allow others to find and evaluate it.
  hds.essex.ac.uk/g2gp/gis/sect101.asp
• Data about data. How the structures and calculation rules are stored, plus, possibly, additional information on data sources, definitions, quality, transformations, date of last update, user access privileges, etc.
  www.olapreport.com/glossary.htm
• A set of information that fully describes each data file in the archive. Metadata stored in the KOA database includes: FITS header keyword values (both those written by the telescope, and those added by the archive processing software); file location information; spatial coordinates and spatial bin assignments; proprietary period information; and certain transformations of original FITS keyword values (for instance, RA and DEC are stored as decimal values; the original FITS sexagesimal ...
  koa.ipac.caltech.edu/deepimpact/glossary.html
• Metadata is the structured description of an object or collection of objects and is similar to what is found in a standard cataloging record. There are three kinds of metadata:
  www.law.harvard.edu/library/collections/digital/guidelines_glossary.php
• A description of data.
  www.epa.gov/cdx/about/glossary.htm
• data about data; "a library catalog is metadata because it describes publications"
  wordnet.princeton.edu/perl/webwn
• Metadata (Greek: meta-+data "information") means data about data. While this definition is commonly offered, it is also commonly not helpful. An example is a library catalog card, which contains data about the nature and location of a book: It is data about the data in the book referred to by the card.
  en.wikipedia.org/wiki/Metadata
• Metadata is the name of a US corporation and a registered trademark in the United States.
  en.wikipedia.org/wiki/Metadata_(corporation)