a native or inhabitant of Australia
"The friendly stranger introduced himself as an Australian during his trip to Sydney."
the Austronesian languages spoken by Australian aborigines
"Scholars have long debated whether any of these ancient australian tongues survived into modern times."
A person from the country of Australia or of Australian descent.
"The australian proudly shared stories about her family's history in Sydney."
In plain English: An Australian is someone who lives down under and follows their own unique culture and rules.
"The friendly Australian waved hello to his new neighbors during their first week in Sydney."
of or relating to or characteristic of Australia or its inhabitants or its languages
"Australian deserts"
"Australian aborigines"
Of, from, or pertaining to Australia, the Australian people or Australian languages.
"The australian kangaroo is an iconic symbol of wildlife found across the continent."
In plain English: Australian describes anything that comes from Australia, such as its people, culture, or things found there.
"The Australian weather was surprisingly warm for autumn."
The word comes from Australia with the suffix -an added to it. This combination creates an adjective meaning "of or relating to Australia."