Who is a nonimmigrant person?
A quick search of the meaning of Nonimmigrant on USCIS.gov online dictionary (glossary) gives the following definition and explanation:
An alien who is admitted to the United States for a specific temporary period of time. There are clear conditions on their stay. There are a large variety of nonimmigrant categories, and each exists for a specific purpose and has specific terms and conditions. Nonimmigrant classifications include:
Foreign government officials;
Visitors for business and for pleasure;
Aliens in transit through the United States;
Treaty traders and investors;
Temporary workers and trainees;
Representatives of foreign information media;
Fiancé(e)s of U.S. citizens;
NATO officials; and
According to USCIS most nonimmigrants can be accompanied or joined by spouses and unmarried minor (or dependent) children.