Actually, that's not entirely accurate. While Australia is often called the largest island in the world, it is actually the largest landmass (or continent) that is also considered an island. Here's why:

1. Size: Australia is the largest island and the smallest continent, with an area of about 7.7 million square kilometers (3 million square miles).

2. Definition of "island": An island is typically defined as a piece of land surrounded by water. However, this definition can be ambiguous when applied to very large landmasses.

3. Continent vs. Island: Geographers generally consider continents to be larger landmasses, while islands are smaller landmasses surrounded by water.

4. Other large islands: Greenland is actually the largest island in the world by land area (2.166 million sq km or 836,330 sq mi), but it's not a continent.

5. Australia's status: Australia is unique because it's both a continent and an island. It's the largest landmass that is entirely surrounded by water and is not connected to any other continental landmass.

So, while Australia is often referred to as the largest island, it's more accurate to say that it's the largest island-continent. If we're strictly talking about islands, then Greenland would be the correct answer.