Taxonomies are the dictionaries used by XBRL. They define the specific tags for individual items of data (such as "net profit"). Different taxonomies will be required for different financial reporting purposes. Different XBRL jurisdictions may have their own financial reporting taxonomies to reflect their local accounting regulations. Many different organisations, including regulators, specific industries or even companies, may require taxonomies to cover their own business reporting needs.

XBRL International has two levels of recognition of taxonomies. Approved Taxonomies have to comply with the official XBRL guidelines for that type of taxonomy, as well as with the XBRL Specification. Acknowledged Taxonomies just have to comply with the XBRL Specification. For more information on the recognition process see Taxonomy Recognition.

For guidance on the design and use of taxonomies, see Taxonomy Guidance in the Technical Support section.