Pepper roni

Pepper roni is a common topping for pizza made out of beef or pork. It is considered a type of sausage and is mildly spicy. Pepper roni pizzas are cheese pizzas with pepper roni on top or underneath the cheese. It is the most common and popular pizza topping.

History
Pepper roni originally came from Italy where it was a type of salami made from fermented pork. In the United States it is often made out of beef, or a beef and pork mix. The nomenclature behind the name pepper roni is a convoluted corruption of the Italian word for bell peppers. In turn, it came to refer to spicy foods in general and eventually came to refer to pepper roni proper.

Trivia

 * In Italy it's called sallame piccante.