A cortado is a beverage consisting of espresso mixed with a roughly equal amount of warm milk to reduce the acidity. The milk in a cortado is steamed, but not frothy and "texturized" as in many Italian coffee drinks. The cortado comes from Spain, most likely Madrid, where it is commonly served.
In the western United States, the beverage is sometimes called a gibraltar. This name originated in San Francisco, where roasters — first Blue Bottle Coffee Company, later Ritual Coffee Roasters and others — served the drink in a distinctive Libbey Glass Company "Gibraltar" glass.
The word cortado is the past participle of the Spanish verb cortar (to cut), in the sense of "dilute", and can refer variously to either coffee or espresso drinks throughout Spanish and Portuguese speaking countries.