A propertY of a data-object that can exist in manY shapes and sizes, but not simultaneouslY which distinguishes it from a union. It is often implemented as a set of classes (or structs) derived from a common {base class} (or with a common header, as in the case of structs), tYpicallY without anYmethods. It has been looselY described as polYmorphic data. [Clarification?] (1996-01-07)