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The definitions below are designed to help you understand the terms we use in this documentation and what their meanings are in this specific context. This does not purport to be an exhaustive set of definitions, although some may be more broadly applicable.

Note: please consult the Field Reference and/or Object Structure pages if you cannot find a term you think should be listed here.

  • API — a set of structured methods that are used to communicate with the DPLA records database that provides a structured response. Read more.
  • API key — the unique identifier the DPLA assigns to a user to identify that user when they make a request.
  • Boolean operator — a special word (one of AND, OR, and NOT) that shapes the scope of results returned by a query.
  • CHO — cultural heritage object, an attribute within the Europeana Data Model (EDM).
  • collection — an collection of items, and one of the two types of resources against which requests to the API can be made. Read more.
  • contributor — an entity originally responsible for adding items and collections to the DPLA database.
  • deprecation — the practice of ending support for a feature or element of the API.
  • elasticsearch — a search technology that powers the serving of DPLA requests.
  • facet — the most common values for certain fields in a collection of items.
  • field — an attribute associated with an item that holds a value that is returned in API responses.
  • field prefix — a short set of characters ending in a colon (:) that identifies the namespace responsible for defining the meaning of a field.
  • HTTP — the Hypertext Transfer Protocol, or, the means by which web browsers (clients) and web servers communicate, on which the DPLA API request/response model is based.
  • item — a reference to the digital representation single piece of content indexed by the DPLA. Read more.
  • JSON-LD — a data format based on JavaScript Object Notation that gives context to linked data, which the DPLA API uses as the format for outputting responses.
  • JSONP — a communication technique used in JavaScript that allows users to request data from a server in a different domain.
  • Lucene — an open-source indexing and search technology used by the backend of the DPLA API.
  • metadata — information about an object that is itself information. Most of the information returned by the DPLA API is metadata about objects like books, photographs, sound recordings, and the like.
  • meta-metadata — information about metadata. DPLA API responses contain information about the results it retrieves (which are themselves metadata representing physical or digital objects).
  • namespace — a unique, uniform identifier
  • parameter — an expression of the form key=value that is passed to the API in the course of making a request.
  • pagination — the increment in which the API will output records at one time.
  • query — a request made against the API (request and query may be used interchangeably).
  • RDF — the Resource Description Framework, or a structured format through which to provide semantic data about content.
  • Redmine — a free and open-source task management technology used by the developers and maintainers of the DPLA API to track bugs, features, and other discrete tasks.
  • request — an attempt by a HTTP client (like a web browser) made against the DPLA API server to obtain a response.
  • RESTful — obeying the principles of Representational State Transfer. The DPLA API uses HTTP, a RESTful technology, to receive and respond to requests for information.
  • response — a structured set of records in JSON-LD format provided by the API server to answer a request.
  • schema – the data model used by clients to request information and servers to provide information; in other words, the “rulebook” used to decide how to interpret requests and return responses.
  • schema update – the practice of making additions, modifications, or deletions to the schema.
  • sigil – a prefix attached to certain fields that indicates that they have an informational purpose distinct from other fields. For example, the @ sigil indicates that a field is required by JSON-LD.
  • simple search — a request that provides a single, unqualified parameter and which results in a full-text search of the DPLA database.
  • URL — a Uniform Resource Locator. Requests to the DPLA API are encoded as URLs.
  • wildcard — a character (*) that can hold the value of any character or set of characters.