Common name


 * See also Naming conventions (common names) and Naming conventions

In science, a common name is any commonly-used name by which a species, other taxon, or other entity is known, other than its scientific name.

Overall, common names have the advantage of being easy to remember and pronounce, and the disadvantage that many of them are unreliable. A serious problem with many common names is the fact that they are by no means universally used, in contrast to scientific names, which are the same in any language, and in any region of the world. Multiple different versions of common names frequently exist, and this can be misleading and confusing.

In any one language, such as the English language, there are a lot of things that have an everyday name, including many things that also have a scientific name. These everyday names are natural words in the language, words that ordinary people actually commonly use on an everyday basis, such as the words dog, salt, or star for example. But because the number of different kinds of entities on Earth is so very great, by no means all entities have a common name. Many non-scientists find it difficult to remember or pronounce scientific names, and because of this many entities or categories of objects which have no real everyday name, have nonetheless been given "common names", many of which are artificial in the sense that they were especially coined for that purpose.

Biology, common names
Broadly defined, a common name for a biological species is any name that is commonly used for the species other than its scientific name, i.e., its binomial. (A binomial is a formal name, and it is the same the world over, independent of the language in use: a binomial is rendered italicised in Roman script, for example, Patella vulgata.) Common names however often do not correspond in any way to scientific names, especially if they are genuine everyday names.

Generally speaking, naturally-occurring common names only exist for those organisms that are reasonably commonly encountered, or are quite noticeable, whether dangerous or edible or useful in some other way. Common names almost always exist for organisms which are, or were, economically important to humans.

These genuine common names are written and spoken in whatever language is used in that particular part of the world. Unfortunately however, these everyday names are often not the same from one small region to another, even within one country. Sometimes there are several different common names for one species even within one region, and fairly often it happens that a species is known by one name when it is a juvenile, and another name when it is an adult.

However, despite all these disadvantages, there are some advantages to the use of common names. Many of our everyday English names for plants and animals like "rat", "squirrel", "rose" or "oak" refer to broad categories. By adding adjectival descriptors, such as the combinations "brown rat", "red squirrel", "dog rose" and "cork oak", common names for individual species have been created and continue to be created.

A common name which is quite useful in local context can be ambiguous if used more widely. Names like "sardine" or "deer" are applied to dozens of different species in English-speaking countries worldwide. Though these two names are perfectly adequate in their original domains of use: (fishing and hunting) in localities where only one such species is known to exist, or is likely to be caught.

Some common names such as "periwinkle" apply both to a mollusk and to a plant.

Official common names
For some groups, such as birds in the US, individual species do have official common names. Such official common names are chosen by a governing body and typically attempt to follow a set of guidelines set by that body. Such names have no standing in scientific nomenclature, but they are an attempt by scientists to communicate with non-scientists who might feel intimidated by scientific names, or by non-scientists trying to create more pleasant-sounding names.

It is debatable how far official common names are actually "common". Much depends on how the methods of composing the list. In the past there has been a fad to have all the species in a genus repeat the genus name, for example if Diospyros is regarded as the "ebony genus", to have all the species include "ebony" in the name. Such a method of creating names is highly artificial and is frowned upon. However, if an official list respects widely used layperson's names it may be beneficial.

Other attempts to standardise common names (insects in New Zealand; freshwater fishes in north America) have met with mixed success, but common names lose some of their unique merits when defined. Undefined use of Māori names for plants in New Zealand has usefully added stability to nomenclature in the face of scientific name changes.

In Australia, Common names for seafood species have been standardised as AS SSA 5300 Australian Fish Names Standard(AFNS) which contains Standard Fish Names for over 4000 species. Previously fish in Australia were sold under a large number of common names. The confusing variety of Australian common names resulted from: the numerous species Australia has on offer (over 4,000 species of finfish and many more crustaceans and molluscs); local and regional variations in the names being used; some species being known by more than one name; and the same name being used for more than one species.

The AFNS was compiled through an exhaustive process involving work by taxonomic and seafood industry experts (including CSIRO) and including input through public and industry consultations by the Australian Fish Names Committe (AFNC). The AFNS has been an official Australian Standard since July 2007 and has existed in draft form (The Australian Fish Names List) since 2001. Seafood Services Australia (SSA) serve as the Secretariat for the AFNC. SSA is an accredited Standards Australia (Australia’s peak non-government standards development organisation) Standards Development Organisation

A set of guidelines for the creation of English names for birds was published in The Auk in 1978.

Common names based on scientific names, and vice versa
In gardening, familiar names like Begonia, Dahlia, Gladiolus, and Rhododendron are common names that usually refer to plants in a genus of the same name (but note that Azalea refers to a genus now submerged in the genus Rhododendron). The use of genus names has been increasing in the vernacular of English-speaking gardeners in recent decades. Gardeners, naturalists and others, typically continue to use old common names when a scientific name changes. This is a useful feature whereby common names lend a measure of stability to nomenclature, and retain historical associations.

Especially with plants, common names (unitalicised) are often the same as their scientific names (italicised and the generic name capitalized). However, the reverse also happens, some pre-existing common names, typically from languages local to the plants, have been used to create the formal binomial. For this, the common names can be Latinized (and possibly anglicized), irrespective of their source language. For example Hoheria is from the New Zealand Māori "Houhere". A local name may also be adopted unaltered: the genus Tsuga is so named after the Japanese "tsugá".

For historical reasons, some common names and 'equivalent' scientific names refer to unrelated species. For example Cranesbill is the common name for the genus Geranium, while the common name Geranium refers to species of the South African genus Pelargonium. Again, the gardeners' 'Nasturtium' is Tropaeolum spec., whereas the European Watercress is in the genus Nasturtium.

Chemistry
In chemistry, official naming of chemical substances follows the IUPAC nomenclature, a convention on systematic names. In addition to its systematic name, a chemical may have one or more common or trivial names (and many widely occurring chemicals do indeed have a common name). Some common names allow a reader with some chemical knowledge to deduce the structure of the compound (e.g., acetic acid, a common name for ethanoic acid). Other common names, while uniquely identifying the compound, do not allow the reader to deduce the structure, unless he or she already knows it. Examples include cinnamaldehyde or morphine.