Text string with the language of the string identified as recommended in the XML 1.0 W3C Recommendation, section 2.12. Name or code with an (optional) authority. If the codeSpace attribute is present, its value shall reference a dictionary, thesaurus, or authority for the name or code, such as the organisation who assigned the value, or the dictionary from which it is taken. Type copied from basicTypes.xsd of GML 3 with documentation edited, for possible use outside the ServiceIdentification section of a service metadata document. Unordered list of one or more commonly used or formalised word(s) or phrase(s) used to describe the subject. When needed, the optional "type" can name the type of the associated list of keywords that shall all have the same type. Also when needed, the codeSpace attribute of that "type" can reference the type name authority and/or thesaurus. If the xml:lang attribute is not included in a Keyword element, then no language is specified for that element unless specified by another means. All Keyword elements in the same Keywords element that share the same xml:lang attribute value represent different keywords in that language. For OWS use, the optional thesaurusName element was omitted as being complex information that could be referenced by the codeSpace attribute of the Type element.