Definition of "sansei"

Born and brought tip mostly in South America, the United States (particularly Hawaii) and Canada, the nisei and sansei have Japanese features but often speak the language imperfectly, if at all. “If you don't speak Japanese well,” one sansei said ruefully, “it's better to he white.”

1973 October 4, Robert Trumbull, “Offspring of Japanese Settlers in U.S. Find Japan Frustrating”, in The New York Times‎

Under these circumstances it may not be unexpected to have the "assimilationist Sansei" protest that he is not a Japanese-Canadian; he is a Canadian, period. None of this hyphenated stuff.

1978, Gordon Hirabayashi, “Japanese Heritage, Canadian Experience”, in Harold Coward, Leslie S. Kawamura, editors, Religion and Ethnicity, Waterloo, Ont.: Wilfrid Laurier University Press, page 66

While hundreds of nisei and sansei are employed by Japanese giants like Sony, Mitsubishi and Honda, many more work with Brazilians as agronomists, artists, doctors, businessmen and engineers. Colleagues [c]all them “modest and respectful.”

1988 May 8, Marlise Simons, “Japanese Gone Brazilian: Unhurried Workaholics”, in The New York Times‎