The literal translation of the word 'Aborigine' is: the people who were here from the beginning. It is not synonymous (doesn't have the same meaning), as the word 'indigenous' as this means originating in an area (latin: indigena = in (in) + ginere (be born) in a particular place.
There is no written record regarding prehistoric Aboriginal Australia. Knowledge of the past is found in archaeological evidence and Aboriginal oral traditions which have been handed down from generation to generation.
Therefore using reliable dates derived from archaeological evidence, theories of the initial colonization of Australia have been determined.
Prior to colonization which began in January 1788, the Australian Aborigines lived a lifestyle based on their Dreamtime beliefs. They had survived as a race for thousands of years and their lifestyle and cultural practices had remained virtually unchanged during that time. We refer to this as the traditional period.
However colonization imposed changes on the Aborigines as people who lived in areas that were being settled by the Europeans, were forced off their land as towns and farms were developed. We identify the period in which the changes took place, as the historical period. The sort of changes that took place usually commenced with explorers entering the area of a tribe and being challenged by the people for trespassing on their land. The Europeans often (usually) responded by shooting at the people. Many were killed. When settlers followed the explorers and began felling trees and building farms, they restricted the ability of the Aborigines to move freely around their land. They also destroyed their traditional food sources.
These changes took place throughout the continent at different times. They began in the Sydney and Parramatta districts from 1788; in the Cowpastures (Campbelltown / Camden)area from the early 1800s and in the Illawarra district from 1815. Gradually - but with increasing speed colonization spread throughout the entire continent.
More at http://theunexplainedmysteries.com/aboriginal.html