An alien who seeks temporary entry to the United States for a specific purpose. The alien must have a permanent residence abroad (for most classes of admission) and qualify for the nonimmigrant classification sought. The nonimmigrant classifications include: foreign government officials, visitors for business and for pleasure, aliens in transit through the United States, treaty traders and investors, students, international representatives, temporary workers and trainees, representatives of foreign information media, exchange visitors, fiance(e)s of U.S. citizens, intracompany transferees, NATO officials, religious workers, and some others. Most nonimmigrants can be accompanied or joined by spouses and unmarried minor (or dependent) children.
Source: U.S. Citizenship and Immigration Services