Sushi is a dish made with cooked, vinegared rice combined with other ingredients. These “other ingredients” are called neta, and they often include raw fish or other seafood. But not always.
Sushi really has nothing to do with raw fish. It refers to the vinegar-seasoned rice used in making what we refer to as sushi. There are many types of this dish that are often wrongly called sushi. Sashimi is simply slices of raw fish. Nigiri is made from forming a handful of rice into a mound and a piece of seafood is placed over the top. Maki rolls are made from wrapping sushi rice and various fillings inside a seaweed wrapper.
Southeast Asians developed the original form of sushi: fish fermented by being wrapped in souring, fermenting rice. The dish spread to southern China before reaching Japan. However, our modern, internationally known sushi, which involves vinegared rice rather than soured, fermented rice, was developed in Japan by a man named Hanaya Yohei in the first half of the 1800s. He was basically creating fast food—food that could be prepared rather quickly and eaten with one's hands. In the early 1980s, Norwegians began to use salmon in sushi, and that innovation spread to Japan.