That basically is what it means, or at least, it's a primary defining characteristic. There are some other relevant characteristics, which make the definition

That basically is what it means, or at least, it's a primary defining characteristic. There are some other relevant characteristics, which make the definition a bit fuzzy. The biggest one is that they need to have retained some identifiable aspects of their culture in the face of subsequent settlement. But to a first approximation, first to settle - or at least being among the first to settle - is the primary basis for determining indigenousness.