Why are hamburgers called hamburgers when they're made from beef and not ham?

Kiryu DIO

Be retarded, do drugs and shit, praise DIO
True & Honest Fan
Apr 12, 2018
I was in one of the food threads and decided to pike up about how I liked chicken burgers more than hamburgers when I had a stark realization: Hamburgers are made from beef, so why are they called hamburgers if they're not made of ham?