Black's Law Dictionary, Sixth Edition, p. 1025

National origin.  "In equal employment opportunities provisions of the Civil Rights Act, term "national origin" on its face refers to country where person was born, or, more broadly from which his or her ancestors came, and was not intended to embrace requirements of United States citizenship.  Espinoza v. Farah Mfg. Co., Inc., Tex., 414 U.S. 86, 94 S.Ct. 334, 336, 38 L.Ed.2d 287." 

[Black's Law Dictionary, Sixth Edition, p. 1025]