Yes th Great Australian Bight is a part of the south coast of Australia.
The body of water south of the Nullarbor Plain is the Great Australian Bight. It is part of the Southern Ocean.
Depending on the context (usage), a bight [as a noun] may be a bay or gulf, a river bend, the body of water surrounded by such a bend (like an oxbow...), the middle part of a rope that is different from the ends of the rope, or the loop or bent part of a rope that is different from the ends. As a verb, it means "to fasten, or bind with a bight of rope". In Australia, the Bight (the Great Australian Bight, that is...) is that major indentation along the South coast, spanning Cape Pasley in Western Australia to the Eyre Peninsula in South Australia.
The Great Australian Bight.
Long ago, the world had only two super continents, Laurasia and Gondwanna. Gondwanna was composed of the southern continents, and these gradually split apart, and in particular, Antarctica separated from Australia. You'll find a good fit between the Australian Bight and part of northern Antarctica. That is the current explanation.
Great Australian Desert is a generic term referring to all the deserts of Australia and the Great Sandy Desert is part of that.
Interestingly, the Great Victoria Desert is not in the Australian state of Victoria. The Great Victoria Desert is in south-western Australia, spanning both South Australia and the eastern section of Western Australia.
The Australian Alps are the highest mountain range on mainland Australia. Part of the Great Dividing Range which extends from the northern tip of Australia right down to Victoria, the Australian Alps are positioned roughly in Australia's southeast, on the border of Victoria and New South Wales.
The Australian Outback is probably the largest part of Australia.
The Great Barrier Reef lies within Australian waters. It is located just off the coast of Queensland.
The Great Barrier Reef lies off the coast of Queensland, so it is considered part of Australia. It lies within Australian waters.
Victoria is a state itself, located in the southeastern part of the Australian mainland. It is not part of Western Australia; nor is it part of South Australia.