In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the tiger cowry of the Indo-Pacific, Cypraea (Cypraea) tigrisLinnaeus, which belongs to the subgenus Cypraea of the genus Cypraea. However, it is not mandatory, or even customary, when giving the name of a species, to include the subgeneric name.
In the International Code of Nomenclature for algae, fungi, and plants (ICNafp), the subgenus is one of the possible subdivisions of a genus. There is no limit to the number of divisions that are permitted within a genus by adding the prefix "sub-" or in other ways as long as no confusion can result.  The secondary ranks of section and series are subordinate to subgenus.  An example is Banksia subg. Isostylis, a subgenus of the large Australian genus Banksia .  The ICNafp requires an explicit "connecting term" to indicate the rank of the division within the genus.  Connecting terms are usually abbreviated, e.g. "subg." for "subgenus", and are not italicized.
In zoological nomenclature, when a genus is split into subgenera, the originally described population is retained as the "nominotypical subgenus" or "nominate subgenus", which repeats the same name as the genus. For example, Panthera (Panthera) pardus, a leopard. In botanical nomenclature the same principle applies, although the terminology is different. Thus the subgenus that contains the original type of the genus Rhododendron is Rhododendron subg. Rhododendron. Such names are called "autonyms". 
Genus is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus.
In taxonomy, binomial nomenclature, also called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name, a binomen, binominal name or a scientific name; more informally it is also historically called a Latin name.
Order is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families.
In biological classification, a subfamily is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoological names with "-inae".
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species have subspecies, but for those that do there must be at least two. Subspecies is abbreviated subsp. or ssp. and the singular and plural forms are the same.
In biology, a tribe is a taxonomic rank above genus, but below family and subfamily. It is sometimes subdivided into subtribes. By convention, all taxonomic ranks from genus upwards are capitalized, including both tribe and subtribe.
The International Code of Nomenclature for algae, fungi, and plants is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "traditionally treated as algae, fungi, or plants". It was formerly called the International Code of Botanical Nomenclature (ICBN); the name was changed at the International Botanical Congress in Melbourne in July 2011 as part of the Melbourne Code which replaced the Vienna Code of 2005.
In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botany and zoology. In zoology, alternate terms such as original combination or protonym are sometimes used instead. Bacteriology uses a similar term, basonym, spelled without an i.
A botanical name is a formal scientific name conforming to the International Code of Nomenclature for algae, fungi, and plants (ICN) and, if it concerns a plant cultigen, the additional cultivar or Group epithets must conform to the International Code of Nomenclature for Cultivated Plants (ICNCP). The code of nomenclature covers "all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria), chytrids, oomycetes, slime moulds and photosynthetic protists with their taxonomically related non-photosynthetic groups ."
In botany, the correct name according to the International Code of Nomenclature for algae, fungi, and plants (ICN) is the one and only botanical name that is to be used for a particular taxon, when that taxon has a particular circumscription, position and rank. Determining whether a name is correct is a complex procedure. The name must be validly published, a process which is defined in no less than 16 Articles of the ICN. It must also be "legitimate", which imposes some further requirements. If there are two or more legitimate names for the same taxon, then the correct name is the one which has priority, i.e. it was published earliest, although names may be conserved if they have been very widely used. Validly published names other than the correct name are called synonyms. Since taxonomists may disagree as to the circumscription, position or rank of a taxon, there can be more than one correct name for a particular plant. These may also be called synonyms.
In zoological nomenclature, the specific name is the second part within the scientific name of a species. The first part of the name of a species is the name of the genus or the generic name. The rules and regulations governing the giving of a new species name are explained in the article species description. For example, the scientific name for humans is Homo sapiens, which is the species name, consisting of two names: Homo is the "generic name" and sapiens is the "specific name".
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections may in turn be divided into subsections.
In botanical nomenclature, author citation is the way of citing the person or group of people who validly published a botanical name, i.e. who first published the name while fulfilling the formal requirements as specified by the International Code of Nomenclature for algae, fungi, and plants (ICN). In cases where a species is no longer in its original generic placement, both the authority for the original genus placement and that for the new combination are given.
In botanical nomenclature, a hybrid may be given a hybrid name, which is a special kind of botanical name, but there is no requirement that a hybrid name should be created for plants that are believed to be of hybrid origin. The International Code of Nomenclature for algae, fungi, and plants (ICNafp) provides the following options in dealing with a hybrid:
A conserved name or nomen conservandum is a scientific name that has specific nomenclatural protection. That is, the name is retained, even though it violates one or more rules which would otherwise prevent it from being legitimate. Nomen conservandum is a Latin term, meaning "a name to be conserved". The terms are often used interchangeably, such as by the International Code of Nomenclature for Algae, Fungi, and Plants (ICN), while the International Code of Zoological Nomenclature favours the term "conserved name".
In botanical nomenclature, autonyms are automatically created names, as regulated by the International Code of Nomenclature for algae, fungi, and plants that are created for certain subdivisions of genera and species, those that include the type of the genus or species. An autonym might not be mentioned in the publication that creates it as a side-effect. Autonyms "repeat unaltered" the genus name or species epithet of the taxon being subdivided, and no other name for that same subdivision is validly published. For example, Rubus subgenus Eubatus is not validly published, and the subgenus is known as Rubus subgen. Rubus.
Priority is a fundamental principle of modern botanical nomenclature and zoological nomenclature. Essentially, it is the principle of recognising the first valid application of a name to a plant or animal. There are two aspects to this:
In zoological nomenclature, an available name is a scientific name for a taxon of animals that has been published conforming to all the mandatory provisions of the International Code of Zoological Nomenclature for the establishment of a zoological name.
In biology, taxonomic rank is the relative level of a group of organisms in an ancestral or hereditary hierarchy. A common system of biological classification (taxonomy) consists of species, genus, family, order, class, phylum, kingdom, domain. While older approaches to taxonomic classification were phenomenological, forming groups on the basis of similarities in appearance, organic structure and behaviour, methods based on genetic analysis have opened the road to cladistics.
In botanical nomenclature, a validly published name is a name that meets the requirements in the International Code of Nomenclature for algae, fungi, and plants for valid publication. Valid publication of a name represents the minimum requirements for a botanical name to exist: terms that appear to be names but have not been validly published are referred to in the ICN as "designations".