An abstract is a short description that summarizes a [CreativeWork](https://schema.org/CreativeWork).
Indicates a page documenting how licenses can be purchased or otherwise acquired, for the current item.
For an [Article](https://schema.org/Article), typically a [NewsArticle](https://schema.org/NewsArticle), the backstory property provides a textual summary giving a brief explanation of why and how an article was created. In a journalistic setting this could include information about reporting process, methods, interviews, data sources, etc.
Conditions that affect the availability of, or method(s) of access to, an item. Typically used for real world items such as an [ArchiveComponent](https://schema.org/ArchiveComponent) held by an [ArchiveOrganization](https://schema.org/ArchiveOrganization). This property is not suitable for use as a general Web access control mechanism. It is expressed only in natural language.
For example "Available by appointment from the Reading Room" or "Accessible only from logged-in accounts ".
Indicates a correction to a [CreativeWork](https://schema.org/CreativeWork), either via a [CorrectionComment](https://schema.org/CorrectionComment), textually or in another document.
The status of a creative work in terms of its stage in a lifecycle. Example terms include Incomplete, Draft, Published, Obsolete. Some organizations define a set of terms for the stages of their publication lifecycle.
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.
Date the content expires and is no longer useful or available. For example a [VideoObject](https://schema.org/VideoObject) or [NewsArticle](https://schema.org/NewsArticle) whose availability or relevance is time-limited, a [ClaimReview](https://schema.org/ClaimReview) fact check whose publisher wants to indicate that it may no longer be relevant (or helpful to highlight) after some date, or a [Certification](https://schema.org/Certification) the validity has expired.
A maintainer of a [Dataset](https://schema.org/Dataset), software package ([SoftwareApplication](https://schema.org/SoftwareApplication)), or other [Project](https://schema.org/Project). A maintainer is a [Person](https://schema.org/Person) or [Organization](https://schema.org/Organization) that manages contributions to, and/or publication of, some (typically complex) artifact. It is common for distributions of software and data to be based on "upstream" sources. When [maintainer](https://schema.org/maintainer) is applied to a specific version of something e.g. a particular version or packaging of a [Dataset](https://schema.org/Dataset), it is always possible that the upstream source has a different maintainer. The [isBasedOn](https://schema.org/isBasedOn) property can be used to indicate such relationships between datasets to make the different maintenance roles clear. Similarly in the case of software, a package may have dedicated maintainers working on integration into software distributions such as Ubuntu, as well as upstream maintainers of the underlying work.
The quantity of the materials being described or an expression of the physical space they occupy.
Indicates the date on which the current structured data was generated / published. Typically used alongside [sdPublisher](https://schema.org/sdPublisher).
A license document that applies to this structured data, typically indicated by URL.
Indicates the party responsible for generating and publishing the current structured data markup, typically in cases where the structured data is derived automatically from existing published content but published on a different site. For example, student projects and open data initiatives often re-publish existing content with more explicitly structured metadata. The [sdPublisher](https://schema.org/sdPublisher) property helps make such practices more explicit.
The "spatial" property can be used in cases when more specific properties (e.g. [locationCreated](https://schema.org/locationCreated), [spatialCoverage](https://schema.org/spatialCoverage), [contentLocation](https://schema.org/contentLocation)) are not known to be appropriate.
Indicates sections of a Web page that are particularly 'speakable' in the sense of being highlighted as being especially appropriate for text-to-speech conversion. Other sections of a page may also be usefully spoken in particular circumstances; the 'speakable' property serves to indicate the parts most likely to be generally useful for speech.
The *speakable* property can be repeated an arbitrary number of times, with three kinds of possible 'content-locator' values:
1.) *id-value* URL references - uses *id-value* of an element in the page being annotated. The simplest use of *speakable* has (potentially relative) URL values, referencing identified sections of the document concerned.
2.) CSS Selectors - addresses content in the annotated page, e.g. via class attribute. Use the [cssSelector](https://schema.org/cssSelector) property.
3.) XPaths - addresses content via XPaths (assuming an XML view of the content). Use the [xpath](https://schema.org/xpath) property.
For more sophisticated markup of speakable sections beyond simple ID references, either CSS selectors or XPath expressions to pick out document section(s) as speakable. For this we define a supporting type, [SpeakableSpecification](https://schema.org/SpeakableSpecification) which is defined to be a possible value of the *speakable* property.
A CreativeWork or Event about this Thing.
The "temporal" property can be used in cases where more specific properties (e.g. [temporalCoverage](https://schema.org/temporalCoverage), [dateCreated](https://schema.org/dateCreated), [dateModified](https://schema.org/dateModified), [datePublished](https://schema.org/datePublished)) are not known to be appropriate.
The schema.org [usageInfo](https://schema.org/usageInfo) property indicates further information about a [CreativeWork](https://schema.org/CreativeWork). This property is applicable both to works that are freely available and to those that require payment or other transactions. It can reference additional information, e.g. community expectations on preferred linking and citation conventions, as well as purchasing details. For something that can be commercially licensed, usageInfo can provide detailed, resource-specific information about licensing options.
This property can be used alongside the license property which indicates license(s) applicable to some piece of content. The usageInfo property can provide information about other licensing options, e.g. acquiring commercial usage rights for an image that is also available under non-commercial creative commons licenses.