The term Down Under refers to which country?

The term Down Under is a colloquialism differently construed to refer to Australia and New Zealand, or the Pacific island countries collectively. The term originally referred solely to Australia and gradually expanded in scope. It comes from the fact that Australia is in the Southern Hemisphere, “below” almost all other countries on the usual arrangement of a map or globe which places cardinal north at the top.

The term has been in use since the late 19th century, and the persistence of the media use of the term has led to its wide acceptance and usage, especially in reference to Australia.