I'm pretty certain an American didn't come up with that particular name. Most people stateside just drink 'coffee'.
'Americano' appears to originate in Italy; It was the derisive term the locals gave to the watered down coffee consumed by Americans (particularly soldiers stationed in Italy during and after WWII).
Most of the different styles of coffee have Italian names in the English speaking world, but these took a long time to be adopted in England itself, where certainly until the middle 1990s when I left for Australia, there were only two types of coffee you could order - 'Coffee', which was weak white coffee; and 'Black coffee' which was the same thing, but without the milk.
On arriving in Australia for my first time in 1994, I arranged to meet some people at a cafe in Brisbane; I got there a little early, so I went to the counter and said "Hello, could I have a cup of coffee please?". "No problem" said the lady behind the counter.
Then we both waited.
It took a surprisingly long time for me to realize that she was waiting for me to place an order; While I was waiting for her to fill the order I believed that I had already made
The reverse occurred to me a few years later, when I returned to the UK for a visit with my family; I had to change planes several times on the trip, and after some 40 hours in transit in various cheap airline seats, my last change was at London Heathrow. Half asleep and in desperate need of refreshment, I slouched up to the counter at the Terminal 1 cafe (Terminal 1 was for domestic UK flights only at that time), and said to the large Afro-Caribbean lady behind the counter "Could I please get a flat white?". This was interpreted as a racial slur, and did not make me popular AT ALL.
I don't know when the English finally decided to adopt the international convention that one should at least attempt to serve decent coffee, and a variety of styles at that; But it was certainly a recent event. At my most recent visit, last year, I noticed a significant improvement in both the quality of food and drink available, and in the attitude of those selling it. I suspect this improvement has largely been driven by the free movement provisions of EU law; And it would be a dreadful shame if Britain were to slip back to the 20th Century 'The customer is always wrong' style of "service" that I recall from my youth.