Computer Dictionary/abstract data type
type's internal form is hidden behind a set of [[Computer Dictionary/access functions|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.