a general specification of the operations allowed on an object, without concerning the actual implementation of these operations, or how the data is stored in memory

a group of data, each of which can store a range of data values and a set of methods or functions that operate on that data

a named data type defined solely through operations for creating and manipulating values of that data type

an ordinary type along with a set of operations

a user-defined type which encapsulates private data together with a set of operations that can be used to manipulate this data

A data type which is defined by the programmer, rather than by the C++ language itself. ADTs include linked lists, doubly-linked lists, queues and trees.

A data type for which only the properties of the data and the operations to be performed on the data are specified, without concern for how the data will be represented or how the operations will be implemented. From [IEEE90].

(ADT): a data declaration packaged together with the functions that operate on it

A data type (usually a collection of objects) that is defined by a set of operations but that can be implemented in a variety of ways.

We use the term abstract data type differently from the usual definition used in computer science research. Here, and abstract data type is a type with a well-defined interface and semantics. Examples of abstract data types are: stack. queue, union-find set, priority queue, etc. Some data types don't have well-defined interfaces, but are useful for implementing abstract data types. We call them implementation types.

an interface and its associated expected behavior, usually implemented as an object containing some data (the internal representation) and a set of methods implementing the interface

A data type is completely characterized by the set of operations that can be applied to its values; thus the internal structure of these values can be hidden and even inaccessible to users of the type. Any imaginable data type can be defined by choosing a representation for its values and writing a subprogram for each operation. This collection of subprograms is an abstract data type. A language that is designed to support user-defined abstract data types has a mechanism for bundling all the subprograms that implement the operations into a single unit; in Ada, this is a package.

A type whose implementation details are hidden and can only be handled using the publicly accessible operations provided for it. Not to be confused with abstract type.

a data type that is not defined into the programming language, but is defined by the programmer; usually, ADTs are used to build high-level, complex structures that model real world objects

A mathematical model that includes a structure for storing data and operations that can be performed on that data. Common abstract data types include sets, trees, and heaps.

A mathematical formalism for defining the characteristics of a certain data type, without revealing the underlying model, let alone any concrete implementation in a computer program. An ADT defines exactly what is required of an implementation, and, by omission, also what is not required.

A specification of a type by giving only the operations that may be applied to values of that type (and, often, some properties of those operations). The term means much the same as interface but is used particularly when specifying data structures.

In computing, an abstract data type (ADT) is a specification of a set of data and the set of operations that can be performed on the data. Such a data type is abstract in the sense that it is independent of various concrete implementations. The definition can be mathematical, or it can be programmed as an interface.