Why did the British call the new mainland Australia?

The unknown land in the south has been legendary for a long time. Matthew Flinders was the first seafarer to sail around the mainland. Before that, this continent was called the Unknown Southern Land, or in Latin it sounded like Terra Australis, but Matthew thought this name was long enough and he suggested his name – Australia. Scientists and geographers of that time liked this name very much and entered into circulation. And in 1824, the British government legally approved this name and exists to this day.