OreoOreo is a type of cookie manufactured by the Nabisco corporation. It consists of a sugary white filling sandwiched between two circular chocolate wafers. A common way to eat an Oreo cookie is to twist apart the wafers so that the filling sticks to one of them, and eat the filling first.
Sometimes people make milkshakes with Oreo cookies in them.
The term is also used, primarily by African-Americans, as a derogatory term for a person who is black by ethnicity, yet whose sympathies lie with whites, often even with white racists. The term implies that the individual so described is "black on the outside, but white on the inside."