Each concept is described on a separate page. Concepts may be classes or properties or yet undefined. Concepts can be organized into one or more vocabularies maintained by a formally designated expert group. When the definitions for concepts are consolidated they can be included into one of the term vocabularies. The wiki approach is based on voluntarily contributions to create and edit concept descriptions and allows users to familiarize themselves with different Sematic MediaWiki functions in a testing environment. The approval of user accounts to this wiki is moderated — please request a user account if you want to use the Sandbox for testing!