In programming languages, an abstract type, unlike Concrete class is a type in a nominative type system which cannot be instantiated. (However, it may have concrete subtypes that do have instances.) An abstract type may have no implementation, or an incomplete implementation. It may include abstract methods or abstract properties that are shared by its subtypes.
A type that is not abstract is called a concrete type.
In many object oriented programming languages, abstract types are known as abstract base classes. In some languages, abstract types with no implementation are known as interfaces. Other names for language features that are (or may be) used to implement abstract types include traits, mixins, flavors, or roles.
Read more about Abstract Type: Signifying Abstract Types, Use of Abstract Types
Famous quotes containing the words abstract and/or type:
“If the world would only build temples to Machinery in the abstract then everything would be perfect. The painter and sculptor would have plenty to do, and could, in complete peace and suitably honoured, pursue their trade without further trouble.”
—Wyndham Lewis (1882–1957)
“Histories of the world omitted China; if a Chinaman invented compass or movable type or gunpowder we promptly “forgot it” and named their European inventors. In short, we regarded China as a sort of different and quite inconsequential planet.”
—W.E.B. (William Edward Burghardt)