Frankfurter use pork only, Wiener use a mixture of pork and beef. Wiener have a circular cross section, the Frankfurter a quadratic cross section with rounded corners. But the Wiener call wiener Frankfurter, whereas Frankfurter call wiener Wiener. The North Americans use the Wiener expression and therefore call wiener Frankfurter and probably don't even know real frankfurter.

Are you still with me? The frankfurter were never called by this name in Frankfurt where they are known since at least the 13th century. The Frankfurter would have asked for a Brühwurst (scalded sausage). But then a Frankfurter butcher emigrated to Wien and had a big success there with his Brühwurst into which he added beef (what was not allowed in Frankfurt). For promotion purposes he called them Wiener Frankfurter which was shortened to frankfurter. Since then (early 19th century), the wiener are known outside of Germany and Switzerland as frankfurter. The success of the Wiener frankfurter made the Frankfurter take action against the name frankfurter (roughly middle of the 19th century). Since then, in Germany, the Frankfurter frankfurter are called frankfurter and this name is restricted to frankfurter produced in or near Frankfurt. In order to discern the Wiener frankfurter, they were then called wiener, a name the Wiener had never used for the Wiener frankfurter.

A frankfurter produced in Germany not near to Frankfurt is called a Saitenwürstchen. A wiener in an intestine (mostly cow) with a larger cross section is called Bockwurst.

I guess the Frankfurter ask for frankfurter if they want frankfurter but ask for wiener if they want wiener which a real Frankfurter of course would never do.

Wolfgang