I’ll just add that I prefer iced americanos to regular iced coffee. In some places iced coffee is prebrewed and placed in a fridge and pulled out when ordered. In contrast iced americanos are always brewed fresh, and I usually get an extra shot.
I suspect that cafes in Ireland and places in the United States may call different things “americano.” The term “flat white” is just coming into trendy use here lately.
It typically is an espresso with extra water, but can mean regular brewed “American” style coffee. It depends where you are. I always think of it as being in countries like Italy that have very strong coffee compared to what we drink in the US, so a cafe in Italy for instance will have an Americano as their weaker version of coffee. I am not a coffee drinker so my knowledge and experience is limited. I guess it’s offered in America also after reading some of the answers here.
I’ve found that some cafes or coffee shops don’t have your standard black coffee (i.e. ‘drip’ coffee), and the closest they can get to that is an Americano, which is simply an espresso with hot water added to dilute it. I’ve ordered black coffees before and been asked “an Americano ok?” http://www.primermagazine.com/wp-content/uploads/2013/02/Americano/Americano_ingredients.jpg