There is a big difference between American coffee and Americano Coffee. And it behooves me to say the latter is becoming more prevalent overseas.
I first encountered the term in Reading, England. In fact, the restaurant was nice enough to provide the definition: Coffee diluted with water. Well, that didn't make any sense. I don't like my coffee diluted water.
The most prevalent form of coffee in the US is drip coffee. You find it everywhere. Every little diner to the largest restaurant serves drip coffee. The result of dripping hot water through a bed of ground coffee is a rather mellowed bitter flavored coffee.
Americano Coffee (or Cafe' Americano in Italy) is produced differently. The beverage is merely espresso diluted with water. That's it.
But the flavor is different. And it's not my favorite. It's stronger and has a flavor that is a forgettable bitter.
So, I get excited with I see a coffee shop in Seoul that actually advertises "Drip Coffee". In fact, the phrase we use in the USA is that we are brewing coffee.
Here is a great website that discusses some of the methods for brewing drip coffee.
I find the flavor of coffee from a French Press is the closest to Americano coffee. But still far enough from it to be enjoyable.