Below are some brief definitions of common terms in XBRL reporting.

XML (eXtensible Markup Language) is a standard created by W3C (World Wide Web Consortium) which allows a user to describe the structure of data. Once the data has been marked up, computer programs and software can intelligently process this data.

XBRL (eXtensible Business Reporting Language) is a form of XML designed specifically for the financial industry to increase efficiency, productivity and transparency in financial reporting.

Tags (markup language) are like bar codes used to markup and define data. In XBRL these tags can identify, describe and provide contextual information for each piece of information. These tags can be understood by a range of software applications allowing data to interface with databases, financial reporting systems and spreadsheets.

Taxonomy is a system or dictionary which contains and organizes all of the tags used to markup a document. Currently XBRL International, the SEC and other organizations are funding the building of standardized taxonomies for the different financial industries in the United States. They are organized under the broad title of U.S.-GAAP/FRIS (U.S. Generally Accepted Accounting Principles/Financial Reporting Instance Standards).

Instance document is a document where financial data has been tagged using XBRL taxonomies.

GAAP is the common set of accounting principles, standards and procedures that companies use to compile their financial statements. GAAP is a combination of authoritative standards (set by policy boards) and simply the commonly accepted ways of recording and reporting accounting information.

A more extensive glossary is available here ^[1]