Also they named Turku just Åbo.

Åbo.

Swedish “å” is an entire word meaning;

a river, a creek, a big stream

“Bo”

bo n

**a dwelling** (of an animal), especially a bird's nest

    fågelbo

        bird’s nest

    att bygga bo

        to build a nest / to nest ("build nest" – idiomatic phrasing)

(poetic, extended from sense 1) **a home**

sätta bo

    settle down

So it’s a three letter word basically saying river-dwelling

I think rather than ask Finns what a place was named they just named them themselves. Perhaps because they were tired of the locals calling everything shit and piss. ¯\_(ツ)_/¯

I knew I wasn’t going to have to link this.

“‘Wales’…? Really, sir?”

“Oh, yes. Don’t you think?”

“What, the vast terra incognito with fauna and flora hitherto undreamt of by sights puts you in mind nothing so much as… Rhyl…?”

“No, of course not. Not North Wales. That’s ridiculous, it’s nothing like North Wales.”

Well that clears things up.