abstract type

In Deriscope terminology, a Deriscope Type is called abstract type when it can have no Deriscope Objects of its own Deriscope Type, i.e. Deriscope Objects of which the ultimate type equals the Deriscope Type here.
For example the Deriscope Type Tradable is abstract type because there can never exist an Deriscope Object of which the ultimate type is Tradable.

An abstract type cannot have the function Create
It may though have other Deriscope Functions