Implementation Details

Just as there is almost always more than one way to remove the epidermis of a feline, there is often more than one way to implement a program.

We call properties and choices made when writing a program that are not related to what that program ultimitely needs to do "implementation details."

As an example, imagine you are about to type a query into Microsoft Bing.¹ The website you go to and the search box you see are intended parts of the program. The fact that if you click search you will see results is also just what the program needs to do.

But all the mechanics of how that query is answered are implementation details.