wasabiPronunciation: /wəˈsɑːbi/Definition of wasabi noun [mass noun] a Japanese plant with a thick green root which tastes like strong horseradish and is used in cookery, especially in powder or paste form as an accompaniment to raw fish. Eutrema wasabi, family Cruciferae Origin: early 20th century: from Japanesewasabi in other Oxford dictionaries Definition of wasabi in the US English dictionary