Sometimes common names are created by authorities on one particular subject, in an attempt to make it possible for members of the general public (including such interested parties as fishermen, farmers, etc.) to be able to refer to one particular species of organism without needing to be able to memorise or pronounce the Latinized scientific name. Creating an "official" list of common names can also be an attempt to standardize the use of common names, which can sometimes vary a great deal between one part of a country and another, as well as between one country and another country, even where the same language is spoken in both places.
A common name intrinsically plays a part in a classification of objects, typically an incomplete and informal classification, in which some names are degenerate examples in that they are unique and lack reference to any other name, as is the case with say, ginkgo, okapi, and ratel. Folk taxonomy, which is a classification of objects using common names, has no formal rules and need not be consistent or logical in its assignment of names, so that say, not all flies are called flies (for example Braulidae, the so-called "bee lice") and not every animal called a fly is indeed a fly (such as dragonflies and mayflies). In contrast, scientific or biological nomenclature is a global system that attempts to denote particular organisms or taxa uniquely and definitively, on the assumption that such organisms or taxa are well-defined and generally also have well-defined interrelationships; accordingly the ICZN has formal rules for biological nomenclature and convenes periodic international meetings to further that purpose.
The form of scientific names for organisms that is called binomial nomenclature is superficially similar to the noun-adjective form of vernacular names or common names which were used by prehistoric cultures. A collective name such as owl was made more precise by the addition of an adjective such as screech. Linnaeus himself published a Flora of his homeland Sweden, Flora Svecica (1745), and in this he recorded the Swedish common names, region by region, as well as the scientific names. The Swedish common names were all binomials (e.g. plant no. 84 Råg-losta and plant no. 85 Ren-losta); the vernacular binomial system thus preceded his scientific binomial system.
Linnaean authority William T. Stearn said:
By the introduction of his binomial system of nomenclature Linnaeus gave plants and animals an essentially Latin nomenclature like vernacular nomenclature in style but linked to published, and hence relatively stable and verifiable, scientific concepts and thus suitable for international use.