I thought about this word recently, when writing about the story often shared about the origins of the word kangaroo. Obviously the word is now most associated with the native people of Australia. This hasn’t always been the case though.
Strictly, the word can refer to the original inhabitants of any region, or at least its inhabitants before colonisation. It comes from the Latin aborigines (first inhabitants), and was originally used to refer to the inhabitants of Latium, the area around Rome. This term may also have come from the phrase ab origine (from the beginning).
The prefix ab, by the way, in this case, means from, as in from this place originally. In Latin it could also mean away, from off, or down, and often had the effect of meaning different from when placed before a word. We can still see this sense in words like abnormal, abject, abhorrent, aberrent, abdicate etc.
The term was therefore used to refer to the original peoples of many places, such as North America, for example. Over time though, it’s come to be used only to refer to the original population of Australia, acquiring official status and a capital A. I think this might be because there were other terms for the indigenous populations of other parts of the world which became more commonly used, like Indians to refer to the native populations of the Americas.
The use of Aborigine or Aboriginal has come to be considered insensitive, with Aboriginal Australian now generally preferred to refer to individuals, as well as the general term Indigenous Australians.
The use of Aborigine, to refer to a single Indigenous Australian, by the way, is due to a linguistic error: the assumption that it was the singular form of the Latin aborigines. Just another reason not to use it, I suppose.