A group of African Americans which limits its membership to "blue veins" or light skinned black people. During the turn of the century there were self-proclaimed Blue Vein Societies in dozens of US cities representing the miniscule Black upper and upper-middle classes. The societies aped partician white "Blue Blood Socieities" (satirzed by Edith Wharton) and their cheif purpose seems to have been to sponsor balls as meeting places for elgible "blue veined" youth.
The African American write Charles W. Chestnutt describes the origin of the term in the quote below when talking about the Cleveland Blue Vein Society.
-- Charles W. Chesnutt, "The Wife of His Youth", 1898