Nisei is a Japanese-language term used in countries in North America and South America to specify the ethnically Japanese children born in the new country to Japanese-born immigrants. The Nisei are considered the second generation and the grandchildren of the Japanese-born immigrants are called Sansei, or third generation. Though nisei means "second-generation immigrant", it often refers to the children of the initial diaspora, occurring in the late 19th and early 20th centuries, and overlapping with the G.I. and silent generations.

Yonsei is a Japanese diasporic term used in countries, particularly in North America and in Latin America, to specify the great-grandchildren of Japanese immigrants (Issei). The children of Issei are Nisei. Sansei are the third generation, and their offspring are Yonsei. For the majority of Yonsei in the Western hemisphere, their Issei ancestors emigrated from Japan between the 1880s and 1924.