In taxonomy, an authoritative document containing a system of rules and recommendations to be followed in giving a scientific name to an animal or animal group. It has been adopted by the International Congresses of Zoology (more recently the International Union of Biological Sciences) and is administered by the International Commission on Zoological Nomenclature. The most recent version of the Code is the Fourth Edition published in September 1999 and took effect on January 1, 2000; usually referred to as the "Code" .