Australia, isn’t it Oceania

America is a single continent too, or 3 subcontinents if you like to divide things.

(Turns out the OP’s definition is completely wrong, but who cares?)

It is? I learnt north and south were separate. So I guess what makes a continent a continent? Also what would the 3 subcontinents be? North, central, south? (Guesses wildly)
Everyone learns different definitions based on their education system’s world view, leading to a number of continents somewhere between 3 and 20. It turns out that nature doesn’t care for humans’ desire to put everything into neat, well-defined little boxes.
I would have hoped it had something to do with tectonic plates

20?!

My own view is 4: Antarctica, Australia, America, Afro-eurasia. I’m not sure how you’d get to 3, unless you disqualified Australia.

I’ve also heard 7: Antarctica, Australia, split North + South America, split Africa + Europe + Asia.

I suppose you could add a few – I’ve heard the phrase “subcontinent of India”, so that could be an 8th continent. Then maybe Greenland for 9. Beyond that, though? IDK what would even make sense.

BRB, I have to go search for expansive continent definitions.

20?!

See

I would have hoped it had something to do with tectonic plates

here.

Ah, the plates! Thank you.
You could discount Antarctica because without all the ice it’s just an archipelago.
Huh, I would think you’d drop Australia before Antarctica. Still, yeah, I suppose that works to get you down to 3.
What would be a reason to exclude Australia? It’s huge, surrounded by ocean and has unique wildlife.

“That’s not a continent, that’s an island with delusions of grandeur!”

Personally, I include it.