In semantic web technologies a namespace is a prefix that is used to distinguish different uses of the same terms, for example, ai:tree and forestry:tree. The short prefix forms of namespaces "ai:" and "forestry:" are themselves shorthand for longer URI prefixes typically defined in an RDF document, for example:
@prefix forestry: ,
@prefix ai: .
@prefix ai:
Used in Chap. 17: page 251