An abstract set of possible values that an instance of the data type may assume, given either implicitly, e.g. INTEGER, REAL, STRING, or explicitly as, for example, in Pascal:

The data type indicates a class of internal representations for those values.

Types may be defined in terms of other more primitive types, such as arrays of integers. Some languages consider procedures or functions as data types, which can also be used in the construction of more complex types.

Unlike a set, a type cannot contain itself (i.e. a type cannot be one its subtypes). This avoids some well-known paradoxes of sets, notably Russell’s paradox. See also abstract data type.