Definition: Australia is a country located in Western Australia, also known as the Northern Territory. It covers an area of approximately 2.6 million square kilometres (970,000 sq mi), which is approximately one-third the size of Europe, with its coastline extending to over 1,580 km (984 miles) from east to west and from north to south. Australia is a member of the Commonwealth of Nations and is known for its vast natural landscapes, including mountains, deserts, rainforests, beaches, rivers, lakes, forests, and wetlands. The word 'Australia' comes from the Old English language (also known as Old Norse), which was used by the Anglo-Saxons in the 7th century BC to refer to a region of the coast on the northwestern side of the Iberian Peninsula, known today as the Spanish Atlantic Ocean. However, this name does not have an actual origin and is likely a spelling mistake or a misappropriation of an existing word. The term "Australia" was first used in English literature by William Shakespeare in his play "Macbeth", where it appears to be the name of a character who has been transformed into a stag. It became more widely used as a noun, referring to any country located in Australia or its territories. In modern times, Australia is often referred to as the "Land Down Under" and is the second most populous country in the world after China. The Australian dollar is the currency of Australia, and it is subdivided into 100 cents, with each cent representing one-fifth of a euro (€) or two US dollars (USD).