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).

An alias for the item.

A description of the item.

A sub property of description. A short description of the item used to disambiguate from other, similar items. Information from other properties (in particular, name) may be necessary for the description to be useful for disambiguation.

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.

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

Indicates a page (or other CreativeWork) for which this thing is the main entity being described. See [background notes](https://schema.org/docs/datamodel.html#mainEntityBackground) for details.

The name of the item.

A person or organization who owns this Thing.

Indicates a potential Action, which describes an idealized action in which this thing would play an 'object' role.

URL of a reference Web page that unambiguously indicates the item's identity. E.g. the URL of the item's Wikipedia page, Wikidata entry, or official website.

A CreativeWork or Event about this Thing.

URL of the item.

A property-value pair representing an additional characteristic of the entity, e.g. a product feature or another characteristic for which there is no matching property in schema.org.<br/><br/> Note: Publishers should be aware that applications designed to use specific schema.org properties (e.g. https://schema.org/width, https://schema.org/color, https://schema.org/gtin13, ...) will typically expect such data to be provided using those properties, rather than using the generic property/value mechanism.

The duration of the item (movie, audio recording, event, etc.) in [ISO 8601 duration format](http://en.wikipedia.org/wiki/ISO_8601).

The upper value of some characteristic or property.

The median value.

The lower value of some characteristic or property.

The 10th percentile value.

The 25th percentile value.

The 75th percentile value.

The 90th percentile value.

The unit of measurement given using the UN/CEFACT Common Code (3 characters) or a URL. Other codes than the UN/CEFACT Common Code may be used with a prefix followed by a colon.

A string or text indicating the unit of measurement. Useful if you cannot provide a standard unit code for [unitCode](https://schema.org/unitCode).

The value of a [QuantitativeValue](https://schema.org/QuantitativeValue) (including [Observation](https://schema.org/Observation)) or property value node. - For [QuantitativeValue](https://schema.org/QuantitativeValue) and [MonetaryAmount](https://schema.org/MonetaryAmount), the recommended type for values is 'Number'. - For [PropertyValue](https://schema.org/PropertyValue), it can be 'Text', 'Number', 'Boolean', or 'StructuredValue'. - Use values from 0123456789 (Unicode 'DIGIT ZERO' (U+0030) to 'DIGIT NINE' (U+0039)) rather than superficially similar Unicode symbols. - Use '.' (Unicode 'FULL STOP' (U+002E)) rather than ',' to indicate a decimal point. Avoid using these symbols as a readability separator.

A secondary value that provides additional information on the original value, e.g. a reference temperature or a type of measurement.