What is a watered-down espresso called?

An Americano is an espresso diluted with water. Well, it’s not quite that simple, but that’s the core of it. An Americano is made by pouring hot water over one or two espresso shots, resulting in a drink of similar volume and strength to regular coffee. The key to an Americano is that it starts with espresso and adopts the flavors and aromas of the espresso, but with a less powerful taste. The origin of the Americano is not certain, but there is a story most people tell. It began during World War II. American soldiers stationed in Italy couldn’t find coffee like they were used to at home. Espresso was the style of coffee served in Italy, and the soldiers found it too strong for their palette. To appeal to the American taste, a cup of hot water was served alongside the espresso and the men poured the water over the espresso to create a more familiar-tasting cup of coffee.

Source: Chamberlain Coffee