“Abstraction is the notion of looking at a group of “somethings” (such as cars, invoices, or executing computer programs) and realizing that they have common themes. You can then ignore the unimportant differences and just record the key data items that characterize the thing (e.g., license number, amount due, or address space boundaries). When you do this, it is called “abstraction”, and the types of data that you store are “abstract data types”. Abstraction sounds like a tough mathematical concept, but don’t be fooled—it’s actually a simplification.”