Dictionary.net

(ADT) A kind of data abstraction where atype's internal form is hidden behind a set of accessfunctions. Values of the type are created and inspected onlyby calls to the access functions. This allows theimplementation of the type to be changed without requiring anychanges outside the module in which it is defined.Objects and ADTs are both forms of data abstraction, butobjects are not ADTs. Objects use procedural abstraction(methods), not type abstraction.A classic example of an ADT is a stack data type for whichfunctions might be provided to create an empty stack, topush values onto a stack and to pop values from a stack.Reynolds paper(http://cis.upenn.edu/~gunter/publications/documents/taoop94.html).Cook paper "OOP vs ADTs" (http://wcook.org/papers/OOPvsADT/CookOOPvsADT90.pdf).