In law, an alien is a foreign-born resident who has not been naturalized and is still a citizen or subject of a foreign country, although definitions and terminology differ across legal systems.
World War II poster
People of various background became naturalized at Kennedy Space Center in Florida (2010). Before the naturalization they were lawfully admitted permanent resident aliens.
A green card, known officially as a permanent resident card, is an identity document which shows that a person has permanent residency in the United States. Green card holders are formally known as la
Alien (law)
…refugee that is admitted to the United States under 8 U.S.C. § 1157 automatically becomes an "immigrant" and then a "special immigrant" after receiving a green card. The usage of the term "alien" dates back to 1790, when it was used in the Naturalization Act and then 1798 when it was used in the Alien and Sedition…
Sample of a Permanent Resident Card (often called a "green card") of the United States (2023)
A 1949 "alien registration receipt card" of a female immigrant, which was issued by the now-abolished Immigration and Naturalization Service (INS) under the Nationality Act of 1940
A 1976 card issued by the INS to John Lennon, stating the following: "This is to certify that [Lennon] has been duly registered according to law and was admitted to the United States as an immigrant."