In the series & in-general in Japan you say where they come from & then Jin (person). Chikyuu-Jin (Earth-Person), Namekku-Jin (Namek-Person), Nihon-Jin (Japan-Person), Deutsch(u/s?)-Jin (German-Person), Amerikka-Jin (America-Person).
But Saiya-Jins are called Saiya-Jins despite coming from...