Original: To order in Italy a very similar food to what in America is called "pepperoni" one would request salamino piccante to get the spicy sausage (but made only of pork beef, and never with meat from other animals as in the american version). Usually the Italian name for a pepperoni pizza is pizza alla diavola (pizza devil-style, very similar in appearance to the pepperoni pizza).
Simplified: Sometimes Chili peppers are called pepperoni Pepperoni is a meat food that is sometimes sliced very thinly and put on pizza.