Source : Free On-Line Dictionary of Computing

abstract data type
     
         (ADT) A kind of {data abstraction} where a
        type's internal form is hidden behind a set of {access
        functions}.  Values of the type are created and inspected only
        by calls to the access functions.  This allows the
        implementation of the type to be changed without requiring any
        changes outside the {module} in which it is defined.
     
        {Objects} and ADTs are both forms of data abstraction, but
        objects are not ADTs.  Objects use procedural abstraction
        (methods), not type abstraction.
     
        A classic example of an ADT is a {stack} data type for which
        functions might be provided to create an empty stack, to
        {push} values onto a stack and to {pop} values from a stack.
     
        {Reynolds paper
        (http://www.cis.upenn.edu/~gunter/publications/documents/taoop94.html)}.
     
        {Cook paper "OOP vs ADTs"
        (http://www.wcook.org/papers/OOPvsADT/CookOOPvsADT90.pdf)}.
     
        (2003-07-03)