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, or Issei. The Nisei, or second generation, in turn are the parents of the Sansei, or third generation. These Japanese-language terms derive from ichi, ni, san, "one, two, three", the ordinal numbers used with sei. Though nisei means "second-generation immigrant", it more specifically often refers to the children of the initial diaspora, occurring during the period of the Empire of Japan in the late 19th and early 20th centuries and overlapping in the U.S. with the Greatest Generation and Silent Generation.