The word sashimi means “pierced body”, i.e. “刺身” = sashimi, where 刺し = sashi (pierced, stuck) and 身 = mi (body, meat). The culture of eating raw fish started in China as early as 500 BCE and the delicacy arrived in Japan during the Heian Period.  This word dates from the Muromachi period, and was possibly coined when the word “切る” = kiru (cut), the culinary step, was considered too inauspicious to be used by anyone other than samurai. This word may derive from the culinary practice of sticking the fish’s tail and fin to the slices in identifying the fish being eaten.
Sushi (すし, 寿司, 鮨?) is a type of food preparation originating in Japan, consisting of cooked vinegared rice (鮨飯 sushi-meshi) combined with other ingredients (ネタ neta) such as seafood, meat, vegetables and sometimes tropical fruits. Ingredients and forms of sushi presentation vary widely, but the ingredient which all sushi have in common is rice (also referred to as shari (しゃり) or sumeshi (酢飯)). Although commonly mistaken for sushi, sashimi, which is also a Japanese delicacy, consists of thinly sliced raw meat or fish and may or may not be served with rice.
The increasing popularity of sushi around the world has resulted in variations typically found in the Western world, but rarely in Japan (a notable exception to this is the use of salmon, which was introduced by Bjorn Eirik Olsen, a Norwegian businessman tasked with helping the Norwegian salmon industry sell more fish in the early 1980s). Such creations to suit the Western palate were initially fueled by the invention of the California roll (a norimaki with crab (later, imitation crab), cucumber, and avocado). A wide variety of popular rolls (norimaki and uramaki) has evolved since. Norway roll is another variant of uramakizushi filled with tamago (omelette), imitation crab and cucumber, rolled with shiso leaf and nori, topped with slices of Norwegian salmon, garnished with lemon and mayonnaise.