A Foreign National - is a term used to describe a person who is not a citizen of the host country in which he or she is temporally residing. It is an individual who is a citizen of any country other than the US. Whether a foreign national is a nonresident or resident alien for tax purposes is determined based on the individual's visa status, purpose of the current visit, and length of stay in the US.

A Nonresident Alien (NRA) - is any person who is not a US Citizen, not a lawful permanent resident (green card holder), and does not meet either the Green Card or the Substantial Presence Test. A nonresident alien is required to file a special tax form, pay tax only on US source income, is subject to special rates, and may qualify for treaty exemptions.