The best-known taxonomic ranks are, in order: life, domain, kingdom, phylum, class, order, family, genus, and species. This assignment to a genus is not immutable; later a different (or the same) taxonomist may assign it to a different genus, in which case the name will also change.ristotle used the words genus and species to mean generic and specific categories. Aristotle and other pre-Darwinian scientists took the species to be distinct and unchanging, with an  essence , like the chemical elements.
The noun EURO has 1 sense: 1. the basic monetary unit of most members of the European Union (introduced in 1999); in 2002 twelve European nations (Germany, France, Belgium, Luxembourg, the Netherlands, Italy, Spain, Portugal, Ireland, Greece, Austria, Finland) adopted the euro as their basic unit of money and abandoned their traditional currencies Familiarity information: EURO used as a noun is very rare.
DEFINITION of 'European Union-EU'. A group of European countries that participates in the world economy as one economic unit and operates under one official currency, the euro. The EU's goal is to create a barrier-free trade zone and to enhance economic wealth by creating more efficiency within its marketplace. Next Up.