New Zealand is known in Maori as Aotearoa. This is now accepted in both languages and appears in the official title of many organisations.
The usual translation of Aotearoa is The Land of the Long White Cloud (from Ao (cloud), tea (white) and roa (long)). However as with many place names the origin cannot be certain and is bound up with Maori mythology.
There are two good explanations: Wikipedia and The 1966 Encyclopedia of New Zealand .
5 days ago