Terminology
RO-Crate: A directory structure that contains a dataset, which is described in an RO-Crate Metadata File.
RO-Crate Root: The top-level directory of the RO-Crate, indicated by the presence of the RO-Crate Metadata File ro-crate-metadata.json (or ro-crate-metadata.jsonld for crates that comply with versions before v1.1 of this specification)
RO-Crate Metadata File: A JSON-LD file stored as ro-crate-metadata.json in the RO-Crate Root. The metadata file describes the RO-Crate with structured data in form of RO-Crate JSON-LD.
RO-Crate Website: Human-readable HTML pages which describe the RO-Crate (i.e. the Root Data Entity, its Data Entities and Context Entities), with a home-page at ro-crate-preview.html (any additional files reside in ro-crate-preview_files/)
Entity: An identified object, which has a given type and is described using a set of properties as a JSON object in the RO-Crate Metadata File. Properties may link to other entities using their identifier key @id.
Type: A classification of objects or their descriptions. The type (or “class”) is given as a short-hand key, mapped by the RO-Crate JSON-LD Context to a URI that has the type definition.
Property: A relationship from one entity to another entity, or to a value. The type of relationship is identified by a URI, mapped to a key by JSON-LD.
Data Entity: A directory, file or other resource that is considered contained by the RO-Crate and described in its RO-Crate Metadata File.
Root Data Entity: A Data Entity of type Dataset, representing the RO-Crate as a whole.
RO-Crate Metadata File Descriptor: A Contextual Entity of type CreativeWork, which describes the RO-Crate Metadata File and links it to the Root Data Entity.
JSON-LD: A JSON-based file format for storing Linked Data. This document assumes JSON-LD 1.0. JSON-LD map JSON keys to URIs using for instance the RO-Crate JSON-LD Context.
JSON: The JavaScript Object Notation (JSON) Data Interchange Format as defined by RFC 7159; a structured text file format that can be programmatically consumed and generated in a wide range of programming languages. The main JSON structures are objects ({}) indexed by keys, sequential arrays ([]) and literal values ("").
Contextual Entity: An entity associated with another Entity, in order to adequately describe it. For example, a Person, Organization (including research projects), item of equipment (IndividualProduct), license or any other thing or event that forms part of the metadata for a Data Entity. Properties of contextual entities may refer to further entities.
Linked Data: A data structure where properties, types and resources are identified with URIs, which if retrieved over the Web, further describe or provide the identified property/type/resource.
URI: A Uniform Resource Identifier as defined in RFC 3986, for example http://example.com/path/file.html - commonly known as URL. In this document the term URI includes IRI, which also permit international Unicode characters. The URI identifies a downloadable resource (e.g. an image) or a concept (e.g. a type definition).
URI Path: The relative path element of an URI as defined in RFC3986 section 3.3, e.g. path/file.html
RO-Crate JSON-LD Context: A JSON-LD context that provides Linked Data mapping for RO-Crate metadata to vocabularies like Schema.org. This mapping assigns meaning to the JSON keys.
RO-Crate JSON-LD: JSON-LD that use the RO-Crate JSON-LD Context and contain RO-Crate metadata, written as if flattened and then compacted according to the rules in JSON-LD 1.0. The RO-Crate JSON-LD for an RO-Crate is stored in the RO-Crate Metadata File.
Linked Data conventions
Throughout this specification, RDF terms (properties, types) are referred to using the keys defined in the RO-Crate JSON-LD Context.
Following Schema.org practice, property names start with lowercase letters and Type names start with uppercase letters.
In the RO-Crate Metadata File the RDF terms use their RO-Crate JSON-LD names as defined in the RO-Crate JSON-LD Context, which is available at https://w3id.org/ro/crate/1.2-DRAFT/context