In the case the words "and" and "the". I couldn't help posting my dumb reply.
One starts with a s.
and one starts with o.
naming rights?.. oO
No difference at all, it's the same piece of water.
The Black Sea is connected by the Bosphorus Strait to the Sea of Marmara, which is connected to the Aegean Sea, which adjoins the Mediterranean Sea, which adjoins the Atlantic Ocean, so yes it's still the same piece of water.
Besides the spelling?<br />
I look at it like the seas akin to different territories within a given ocean... Just the understanding of a simplistic mind.
Ocean is bigger than a sea