An immigration term for certain people who may be eligible for U.S. permanent residence (a "green card") based on family relationships. Preference relatives include the married children of U.S. citizens, children over 21 of U.S. citizens, the spouses or children of U.S. green card holders, and brothers and sisters of U.S. citizens where the U.S. citizen is at least 21 years old. Preference relatives must usually wait to get a green card, because only around 480,000 are available to them in total each year. Their place in line is based on their "priority date," which is the date when their U.S. citizen or permanent resident petitioner first submitted an I-130 visa petition to U.S. Citizenship and Immigration Services (USCIS) indicating willingness to sponsor the immigrant.