In computer programming, indirection (also called dereferencing) is the ability to reference something using a name, reference, or container instead of the value itself
This is essentially everywhere. The primary example is pointers.
The difference between indirection and [[abstraction]] is pretty muddy. One take that makes the most sense to me is that abstraction is about simplification, and indirection is about location. In this sense, indirection is a special type of abstraction.
- Abstraction is a mechanism that "hides" complicated details of a object in terms of simpler, easier to manipulate terms. In programming, a good example is the difference in details between machine code and the various tools for creating applications that are ultimately based on machine code. Consider creating a Windows Form application with the Visual Studio IDE. The IDE lets you think of the application in terms of easy-to-manipulate items in a What-You-See-Is-What-You-Get manner. The position of a screen widget is abstracted out to a visual location in a frame which you can change by dragging the widget around. Internally, the IDE manipulates the widget using another layer of abstraction such as a high level language (such as C#). C# itself is not manipulated using machine code, it is manipulated using a "Common Runtime Environment" which itself is an abstraction of a computer and operating system.
- Indirection refers to making the location of an item transparent. If you know a web resource's URI, you can access the resource without knowing its precise location. You do not access the resource directly, instead you access through a channel that passes your request through a series of servers, applications and routers. Indirection may be considered to be a special type of abstraction where the location is abstracted. https://softwareengineering.stackexchange.com/questions/111756/what-is-the-difference-between-layer-of-abstraction-and-level-of-indirection