Metadata
Metadata (also Meta data) is data about data, that is information about other information. This is often useful. Libraries usually group books by subject and keep a catalog of the books. In that context the metadata in the catalog include various pieces of information including the author and the subject it is classified under. The index and table of contents of a book also present metadata.
Digital cameras allow people to take pictures. Here the data is the picture taken, and the metadata is information about the picture taken, like when (the date and time), photographic exposure, focal length and other technical details about how the camera made the picture. Some cameras, especially smartphones, have GPS and can include the location in metadata.
Metadata Media
In the 21st century, metadata typically refers to digital forms, but traditional card catalogs contain metadata, with cards holding information about books in a library (author, title, subject, etc.).
Metadata can come in different layers: This physical herbarium record of Cenchrus ciliaris consists of the specimens as well as metadata about them, while the barcode points to a digital record with metadata about the physical record.
Metadata for a Sphagnum papillosum pot that is part of a common garden experiment at Universität Greifswald
An introduction to FAIR data and persistent identifiers
