The name "Australia" is rooted in the Latin term Terra Australis Incognita, which means "unknown southern land." This name was used to refer to a hypothetical continent in the Southern Hemisphere, a concept that had been part of ancient maps. Although the term "Australia" appeared on 16th-century maps, it was not used to identify the modern continent of Australia.

During the 17th century, when the Dutch first explored and mapped the region, they referred to it as "New Holland." However, it was the British explorer Matthew Flinders who popularized the name "Australia" after he circumnavigated the continent in 1803. Despite Flinders' efforts, his published account in 1814 still used the term Terra Australis to describe the continent.

In 1817, New South Wales Governor Lachlan Macquarie formally recommended "Australia" as a replacement for "New Holland." This suggestion gained traction, and by 1824, the British Admiralty officially adopted the name. In 1828, the British Parliament also recognized "Australia" in its legislation. The name was further cemented when the United Kingdom Hydrographic Office included it in The Australia Directory in 1830.

The official title "Commonwealth of Australia" was formalized in 1900 through the Commonwealth of Australia Constitution Act, which marked the country's transition to a unified federation of the six former British colonies.

Today, Australia is affectionately known by several colloquial names, including "Oz," "Straya," and "Down Under," reflecting the nation’s vibrant identity and its global recognition.