The [observationAbout](https://schema.org/observationAbout) property identifies an entity, often a [Place](https://schema.org/Place), associated with an [Observation](https://schema.org/Observation).

Provides additional qualification to an observation. For example, a GDP observation measures the Nominal value.

Identifies the denominator variable when an observation represents a ratio or percentage.

Represents the length and pace of a course.

The total number of students that have enrolled in the history of the course.

Indicates (typically several) Syllabus entities that lay out what each section of the overall course will cover.

Indicates a property used as a constraint. For example, in the definition of a [StatisticalVariable](https://schema.org/StatisticalVariable). The value is a property, either from within Schema.org or from other compatible (e.g. RDF) systems such as DataCommons.org or Wikidata.org.

A subproperty of [measurementTechnique](https://schema.org/measurementTechnique) that can be used for specifying specific methods, in particular via [MeasurementMethodEnum](https://schema.org/MeasurementMethodEnum).

Indicates the origin of a shipment, i.e. where it should be coming from.

The [mobileUrl](https://schema.org/mobileUrl) property is provided for specific situations in which data consumers need to determine whether one of several provided URLs is a dedicated 'mobile site'. To discourage over-use, and reflecting intial usecases, the property is expected only on [Product](https://schema.org/Product) and [Offer](https://schema.org/Offer), rather than [Thing](https://schema.org/Thing). The general trend in web technology is towards [responsive design](https://en.wikipedia.org/wiki/Responsive_web_design) in which content can be flexibly adapted to a wide range of browsing environments. Pages and sites referenced with the long-established [url](https://schema.org/url) property should ideally also be usable on a wide variety of devices, including mobile phones. In most cases, it would be pointless and counter productive to attempt to update all [url](https://schema.org/url) markup to use [mobileUrl](https://schema.org/mobileUrl) for more mobile-oriented pages. The property is intended for the case when items (primarily [Product](https://schema.org/Product) and [Offer](https://schema.org/Offer)) have extra URLs hosted on an additional "mobile site" alongside the main one. It should not be taken as an endorsement of this publication style.

A URL template (RFC 6570) for a checkout page for an offer. This approach allows merchants to specify a URL for online checkout of the offered product, by interpolating parameters such as the logged in user ID, product ID, quantity, discount code etc. Parameter naming and standardization are not specified here.

An Amazon Standard Identification Number (ASIN) is a 10-character alphanumeric unique identifier assigned by Amazon.com and its partners for product identification within the Amazon organization (summary from [Wikipedia](https://en.wikipedia.org/wiki/Amazon_Standard_Identification_Number)'s article). Note also that this is a definition for how to include ASINs in Schema.org data, and not a definition of ASINs in general - see documentation from Amazon for authoritative details. ASINs are most commonly encoded as text strings, but the \[asin\] property supports URL/URI as potential values too.

Indicates the availability type of the game content associated with this action, such as whether it is a full version or a demo.

A country where a particular merchant return policy applies to, for example the two-letter ISO 3166-1 alpha-2 country code.

Used to tag an item to be intended or suitable for consumption or use by adults only.

An organization identifier as defined in [ISO 6523(-1)](https://en.wikipedia.org/wiki/ISO/IEC_6523). The identifier should be in the `XXXX:YYYYYY:ZZZ` or `XXXX:YYYYYY`format. Where `XXXX` is a 4 digit *ICD* (International Code Designator), `YYYYYY` is an *OID* (Organization Identifier) with all formatting characters (dots, dashes, spaces) removed with a maximal length of 35 characters, and `ZZZ` is an optional OPI (Organization Part Identifier) with a maximum length of 35 characters. The various components (ICD, OID, OPI) are joined with a colon character (ASCII `0x3a`). Note that many existing organization identifiers defined as attributes like [leiCode](https://schema.org/leiCode) (`0199`), [duns](https://schema.org/duns) (`0060`) or [GLN](https://schema.org/globalLocationNumber) (`0088`) can be expressed using ISO-6523. If possible, ISO-6523 codes should be preferred to populating [vatID](https://schema.org/vatID) or [taxID](https://schema.org/taxID), as ISO identifiers are less ambiguous.

A [Grant](https://schema.org/Grant) that directly or indirectly provide funding or sponsorship for this item. See also [ownershipFundingInfo](https://schema.org/ownershipFundingInfo).

The taxonomic rank of this taxon given preferably as a URI from a controlled vocabulary – typically the ranks from TDWG TaxonRank ontology or equivalent Wikidata URIs.

Closest parent taxon of the taxon in question.

Closest child taxa of the taxon in question.

A specification in form of a line notation for describing the structure of chemical species using short ASCII strings. Double bond stereochemistry \ indicators may need to be escaped in the string in formats where the backslash is an escape character.

The monoisotopic mass is the sum of the masses of the atoms in a molecule using the unbound, ground-state, rest mass of the principal (most abundant) isotope for each element instead of the isotopic average mass. Please include the units in the form '<Number> <unit>', for example '770.230488 g/mol' or as '<QuantitativeValue>.

This is the molecular weight of the entity being described, not of the parent. Units should be included in the form '<Number> <unit>', for example '12 amu' or as '<QuantitativeValue>.

The empirical formula is the simplest whole number ratio of all the atoms in a molecule.