So about the “seven seas”, it’s obvious the modern interpretation of dividing the atlantic & pacific oceans into north & south are a means to pigeon-hole five oceans (atlantic, pacific, indian, artic & antartic) into that magic number seven.
What about the number of continents? In the states as kids we learn of the seven continents. north & south america, europe, asia, africa, australia, & antartica. but i’ve heard some europeans count only five landmasses: the americas, eurasia, africa, …
So how many continents are there? seven? five? eight (counting “oceania” - all the pacific islands / cultures rolled together)?
Back to the origins of “Seven Seas”, remember that the Devil, when referring to his contract for your soul, says, “It’s the standard contract. Gives you seven wishes in accordance with the mystic rules of life. Seven Days of the Week, Seven Deadly Sins, Seven Seas, Seven Brides for Seven Brothers…”
Yeah, I can’t really see any justification for separating Eurasia from Africa, if you’re not going to also separate North and South America. Both are connected only by a narrow isthmus which now has a canal across it.
The historic justification is that the early Greeks didn’t know that you could loop around the Black Sea, or that the Isthmus of Suez existed. By the time these things were understood, the threefold division had become established.
I read Michael Brown’s book about the renaming of Pluto from a planet to a minor planet. He pointed out defining a planet was fraught with difficulty, and most solutions were fiddled so that the 9 planets fitted the proposed definition, and no other celestial bodies.
As he said, trying to define a continent is much the same - the definition of a continent is one that includes the landmasses we currently call continents - there are no simple scientific criteria. Our definitions generally include arbitrary size boundaries or suchlike.
Oceans, seas etc are much the same. We all KNOW which is which - but your definition is as good as mine. Rivers as well. (What’s the difference between a river, a stream, a creek and a brook?)
Which became impossible once Eris was discovered, since it’s larger than Pluto. Nor are they appreciably different in properties other than size. Which is what set off the chain of events that led Pluto to be promoted to a planetoid instead of a planet.
And yes, I said promoted. The move was much to Pluto’s benefits. Now, instead of being the ugly duckling among the planets, it’s… Well, not the king, but at least a duke of the planetoids.
Oh, and it’s a crick if you can step over it, a creek if you can’t step over it but can jump over it, and a brook if you can’t do either, but it’s shallow enough you can walk across without getting your socks wet.
Wikipedia (under “List of tectonic plates”) classifies 7 primary plates (the ones I listed plus Pacific). Indian is a “secondary” plate along with Caribbean and Arabian plates among others. So I suppose you could make a case for Oceania on the Pacific plate…