Oceanic, a.
Etymology: [Cf.F. océanique. See Ocean.]
1. Of or pertaining to the ocean; found or formed in or about, or produced by, the ocean; frequenting the ocean, especially mid-ocean. Petrels are the most aërial and oceanic of birds. Darwin.
2. Of or pertaining to Oceania or its inhabitants.
Shades of meaning
Fernald has no entry of its own for oceanic; he lists it under nautical.
Where he writes about it:
Ocean, used adjectively, is applied to that which belongs to or is part of the ocean; oceanic may be used in the same sense, but is especially applied to that which borders on (or upon) or is connected with, or which is similar to or suggestive of an ocean; we speak of ocean currents, oceanic islands, or, perhaps, of an oceanic intellect. — from nautical