Dear haikuers, Ryan, community.
Lots of good suggestions here, that's for sure. Obviosly a lot of people have given this a good deal of thought. I am therefore a bit embarassed to have stumbled upon the correct answer to the question without applying myself much at all. I was just struck by it when I read this thread. In other words; I know what the name is.
Before I divulge the secret, I would like to make a few observations:
A lot of people have suggested Japanese words. Most of which I have never heard before. Although Haiku is a Japanese word, I don't think we want to make Haiku a Japanese OS. Personally, I am very attracted to Japanese culture. But Haiku should not become an OS for orientalists. I agree with the comment from the Japanese gentleman, that "haiku" probably should be the only Japanese word in Haiku. Haiku should be international.
The really great thing about the word "Haiku" is that it is known all over the world. It's not simply a Japanese word. It has a reference in Norwegian dictionaries, for instance. It's something that a national culture has given to the international community. That's why it's such a good name!
It also has a bit of a "geek" feel to it, I think. But that might be just a "Be" thing. It certainly pays hommage to the original BeOS. But I have a feeling that the Be guys chose to make Net+ error messages haikus - because that was really geeky in the first place. Anyone knows?
There may be more words like this. Words that don't have to be translated. (Safari is such a word, I think, but it's taken.)From my own national culture, "Viking" and "Troll" are words that are widely known. Not that I'm suggesting the browser should be named "Troll"! ("Viking" could actually work, they were great navigators, but I'm not suggesting that either.)
But "Tranquility"? No. I'm sorry. Its meaning is something agreeable, but I would have to look it up in the dictionary, because I'm not English... British... American... Native Anglish Speaking...
Actually, finding genuinly English words that have that quality could prove to be difficult - because of English being the "lingua franca".
So - the name for the browser? (Ra-tatt-ta-tah!) It's "Mir".
It's the name of the first real multinational space station. (space-cyberspace?)
It means "world", "village" and "Peace".
It's in Russian, but it's widely known.
I rest my case.
Edit: Oh! And it would make a great icon too!