IRS Terms and Definitions
Resident
Meets "green card" or "substantial presence" test. See IRS Pub. 519 - US Tax Guide for Aliens
Nonresident
A non US citizen DOES NOT meet "green card" test or the substantial presence test
U.S. Person
(cf. IRC 7701(a) (30) and Treas. Reg. 1.1441-1(c) (2)). US citizen individual, resident alien individual, US corporation, US partnership, US partner, US trust, US estate, US government, State government, government of District of Columbia, and any other person is not a foreign person.
Foreign Person
(cf. Treas. Reg. 1.1441-19(c) (2)). Nonresident alien individual, foreign corporation, foreign partnership, foreign partner, foreign trust, foreign estate, foreign government, foreign branch of a US person, international organization, and any other person who is not a US person.
