In computing, indirection refers to fetching data (sometimes one or more instructions) from an area of memory indicated by the contents of some memory location, rather than directly from that memory location. (Makes sense, doesn't it?)
The word "indirection" is most often used in the context of assembly language programming; I first encountered it in UNIVAC Series 1100 assembly language. High level programming languages tend to refer to "array indexing" or "pointer dereferencing" to mean the same kind of thing.
With the boom of high level languages and object oriented programming, "indirection" is falling into disuse except in compiler design and other specialized fields.