 Speaking in general, name changes for nomenclatural reasons have become less frequent over time as the rules of nomenclature allow for names to be conserved, so as to promote stability of scientific names.In zoological nomenclature, codified in the "International Code of Zoological Nomenclature", synonyms are different scientific names of the same taxonomic rank that pertain to that same taxon.For example, a particular species could, over time, have had two or more species-rank names published for it, while the same is applicable at higher ranks such as genera, families, orders, etc.