USCISBrE/ˌjuː es siː aɪ ˈes/NAmE/ˌjuː es siː aɪ ˈes/abbreviationUnited States Citizenship and Immigration Services (theUSgovernmentdepartmentthatdealswithpeoplefromothercountrieswhowanttovisitorliveintheUSortobecomeaUScitizen, partoftheDepartmentofHomelandSecurity)美国公民及移民事务署(隶属美国国土安全部)