Who named Australia Australia?

The name "Australia" was first proposed by sea explorer Matthew Flinders in the early 1800s, as part of the full name Terra Australis, meaning Southern Land. The actual name "Australia" was then adopted in 1824.

The name Australia comes from the Latin term 'terra australis incognita', meaning "unknown southern land", because for so long the continent of Australia was theorised, but not realised.