This term [uses](http://blog.schema.org/2012/11/good-relations-and-schemaorg.html) terminology from the GoodRelations Vocabulary for E-Commerce, created by Martin Hepp. GoodRelations is a data model for sharing e-commerce data on the Web. More information about GoodRelations can be found at [http://purl.org/goodrelations/](http://purl.org/goodrelations/).
Schema Version 3.3