In biology, a type is a particular specimen of an organism to which the scientific name of that organism is formally associated

A taxon is a scientifically named grouping of organisms with other like organisms, a set that includes some organisms and excludes others, based on a detailed published description (for example a species description) and on the provision of type material, which is usually available to scientists for examination in a major museum research collection, or similar institution.

Historically speaking, species are described by taxonomists and this description consists of observations made on a Type specimen. The Type specimen is representative of a species but need not be 'typical' in appearance. The Type specimen acts as the 'name bearer' for that species.

By comparing other specimens with the Type specimen (or the description of the Type specimen) it can be determined if these other specimens belong to the same species.

Type specimens are catalogued and usually kept in a museum or other collection where scientists can access it.

Different sorts of 'primary' Type specimen exist:

• Holotype - a single specimen that is the name bearer of the species.
• Syntype - when a species is first described the author may choose several specimens as being representative of the species rather than pick a single holotype. Each specimen is known as a syntype.
• Lectotype - a specimen that was selected (often from a group of syntypes) after the first description of the species to act as a holotype.
• Paratype - other specimens that are listed as representative when a species is described in addition to a holotype.
• Neotype - a specimen selected to act as the holotype for a species after the species was first described and the original holotype was lost or destroyed.
• Plesiotype - a specimen on which a later description was based.