Why Is a Hamburger Named After a German City?
he hamburger did not receive its name because it contains ham. Its name leads back to Hamburg, the German port city.
During the nineteenth century, dishes described as Hamburg steak appeared in Europe and the United States. They generally consisted of chopped or minced beef, sometimes seasoned with onions, pepper, or other ingredients. Hamburg was strongly associated with trade and migration, and foods carrying its name traveled with German speaking immigrants across the Atlantic.
American restaurants began serving Hamburg steak during the late nineteenth century. It was usually eaten from a plate rather than held in the hands. Eventually, vendors placed cooked ground beef between pieces of bread, creating what menus began calling a hamburger sandwich. Over time, sandwich disappeared from the name, leaving hamburger and then simply burger.
Exactly who first put the meat into bread remains disputed. Several American cooks, restaurants, and fairground vendors later claimed the invention, but the evidence is too uncertain to crown one creator. The modern hamburger probably emerged gradually as portable food became useful at lunch counters, fairs, factories, and roadside stands.
The linguistic path is clearer than the invention story. Hamburger originally meant something or someone from Hamburg, just as Frankfurter refers to Frankfurt. Once people shortened hamburger to burger, the ending began behaving like an independent word. That allowed cheeseburger, veggie burger, and countless other variations to appear.
A hamburger is therefore neither a sandwich made in Hamburg nor a meal built from ham. It is an American development whose name preserves the memory of an earlier German beef dish.
Source: Hamburger: A Global History, Andrew F Smith - The Oxford Companion to American Food and Drink, Andrew F Smith

Nasir al-Mulk Mosque, Shiraz, Iran
Source: By Laurens R. Krol