"belonging to the class next after the first," 1833, from the noun phrase (1810) indicating the second of a ranked series of classes (originally in a university, later of railroad accommodations, etc.), from second (adj.) + class (n.). The phrase second-class citizen is recorded from 1942 in U.S. history.
The Negro recognizes that he is a second-class citizen and that status is fraught with violent potentialities, particularly today when he is living up to the full responsibilities of citizenship on the field of battle. [Louis E. Martin, "To Be or Not to Be a Liberal," in The Crisis, September 1942]
updated on March 22, 2022