Aboriginal, a.
Etymology: [See Aborigines.]
1. First; original; indigenous; primitive; native; as, the aboriginal tribes of America. "Mantled o'er with aboriginal turf." Wordsworth.
2. Of or pertaining to aborigines; as, a Hindoo of aboriginal blood.
1 other Webster entry under this spelling
Aboriginal, n.
1. An original inhabitant of any land; one of the aborigines.
2. An animal or a plant native to the region. It may well be doubted whether this frog is an aboriginal of these islands. Darwin.
Shades of meaning
Fernald has no entry of its own for aboriginal; he lists it under primeval.
Where he writes about it:
Aboriginal (L. ab, from, origo, origin) signifies pertaining to the aborigines or earliest known inhabitants of a country in the widest sense, including not merely human beings but inferior animals and plants as well. — from primeval
Aboriginal, autochthonic, and primeval combine the meanings of ancient and original; aboriginal inhabitants, autochthonic races, primeval forests. — from primeval