Pepperoni is a spicy Italian-American variety of salami usually made from pork and beef, It is a descendant of the spicy salamis of Southern Italy, such as salsiccia Napoletana piccante, a spicy dry sausage from Naples or the Soppressata from Calabria. Pepperoni is a popular pizza topping in American-style pizzerias. Also, it is sometimes used to make sub sandwiches. Carrying the title of the literal Italian translation of "peppers", Pepperoni is often recognized as the American counterpart to Spanish-style chorizo, which is usually similar in color and flavor.
The term Pepperoni is a corruption of peperoni, the Italian plural of peperone. While in Italian peperoni refers to bell peppers, in Italian-American cuisine the word "pepperoni" evolved to indicate a kind of spicy sausage.
To order the American version of pepperoni in Italy, someone would request salame piccante or salamino piccante (hot salami, generally typical of Calabria). The Italian name for a pepperoni pizza is pizza alla diavola (with hot sausages).
Throughout continental Europe, peperone is a common word for various types of capsicum including bell peppers and a small, spicy and often pickled pepper known as peperoncino or peperone piccante in Italy and pepperoncini or banana peppers in the US.
Unlike in Europe, the English word, pepperoni, is used as a singular uncountable noun.