The identifier property represents any kind of identifier for any kind of [Thing](https://schema.org/Thing), such as ISBNs, GTIN codes, UUIDs etc. Schema.org provides dedicated properties for representing many of these, either as textual strings or as URL (URI) links. See [background notes](https://schema.org/docs/datamodel.html#identifierBg) for more details.

Indicates an item or CreativeWork that this item, or CreativeWork (in some sense), is part of.

An additional type for the item, typically used for adding more specific types from external vocabularies in microdata syntax. This is a relationship between something and a class that the thing is in. Typically the value is a URI-identified RDF class, and in this case corresponds to the use of rdf:type in RDF. Text values can be used sparingly, for cases where useful information can be added without their being an appropriate schema to reference. In the case of text values, the class label should follow the schema.org [style guide](https://schema.org/docs/styleguide.html).

Actual bytes of the media object, for example the image file or video file.

Media type typically expressed using a MIME format (see [IANA site](http://www.iana.org/assignments/media-types/media-types.xhtml) and [MDN reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types)), e.g. application/zip for a SoftwareApplication binary, audio/mpeg for .mp3 etc. In cases where a [CreativeWork](https://schema.org/CreativeWork) has several media type representations, [encoding](https://schema.org/encoding) can be used to indicate each [MediaObject](https://schema.org/MediaObject) alongside particular [encodingFormat](https://schema.org/encodingFormat) information. Unregistered or niche encoding and file formats can be indicated instead via the most appropriate URL, e.g. defining Web page or a Wikipedia/Wikidata entry.

An image of the item. This can be a [URL](https://schema.org/URL) or a fully described [ImageObject](https://schema.org/ImageObject).

A category for the item. Greater signs or slashes can be used to informally indicate a category hierarchy.

The category or type of credential being described, for example "degree”, “certificate”, “badge”, or more specific term.

URL of the item.

Indicates a target EntryPoint, or url, for an Action.

The URL of a node in an established educational framework.

An associated logo.

A link to the page containing the comments of the CreativeWork.

Genre of the creative work, broadcast channel or group.

A resource that was used in the creation of this resource. This term can be repeated for multiple sources. For example, http://example.com/great-multiplication-intro.html.

Keywords or tags used to describe some item. Multiple textual entries in a keywords list are typically delimited by commas, or by repeating the property.

A license document that applies to this content, typically indicated by URL.

The publishingPrinciples property indicates (typically via [URL](https://schema.org/URL)) a document describing the editorial principles of an [Organization](https://schema.org/Organization) (or individual, e.g. a [Person](https://schema.org/Person) writing a blog) that relate to their activities as a publisher, e.g. ethics or diversity policies. When applied to a [CreativeWork](https://schema.org/CreativeWork) (e.g. [NewsArticle](https://schema.org/NewsArticle)) the principles are those of the party primarily responsible for the creation of the [CreativeWork](https://schema.org/CreativeWork). While such policies are most typically expressed in natural language, sometimes related information (e.g. indicating a [funder](https://schema.org/funder)) can be expressed using schema.org terminology.

Indicates (by URL or string) a particular version of a schema used in some CreativeWork. This property was created primarily to indicate the use of a specific schema.org release, e.g. `10.0` as a simple string, or more explicitly via URL, `https://schema.org/docs/releases.html#v10.0`. There may be situations in which other schemas might usefully be referenced this way, e.g. `http://dublincore.org/specifications/dublin-core/dces/1999-07-02/` but this has not been carefully explored in the community.

A thumbnail image relevant to the Thing.

Link to the drug's label details.

Link to prescribing information for the drug.

Any FDA or other warnings about the drug (text or URL).

The type of fuel suitable for the engine or engines of the vehicle. If the vehicle has only one engine, this property can be attached directly to the vehicle.