In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, trivial name, trivial epithet, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; this kind of name is often contrasted with the scientific name for the same organism, which is Latinized. A common name is sometimes frequently used, but that is by no means always the case.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 Latinizedscientific 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.

The doctrine of common purpose, common design, joint enterprise, or joint criminal enterprise is a common law legal doctrine that imputes criminal liability to the participants in a criminal enterprise for all that results from that enterprise. A common application of the rule is to impute criminal liability for wounding a person to participants in a riot who knew, or were reckless as to knowing, that one of their number had a knife and might use it, despite the fact that the other participants did not have knives themselves. In England and Wales and certain other Commonwealth countries, this was the understanding of the courts until February 2016, when the Supreme Court of the United Kingdom and the Judicial Committee of the Privy Council jointly ruled that it was wrong, and that nothing less than intent to assist the crime would do.The common purpose doctrine was established in England and Wales, and later adopted in other common law jurisdictions including Scotland, Ireland, Australia, Trinidad and Tobago, Solomon Islands, Texas, Massachusetts, the International Criminal Court, and the International Criminal Tribunal for the former Yugoslavia.

Common moorhen
Gallinula chloropus
G. chloropus