An operation is some action one object performs upon another in order to elicit a reaction. - Grady Booch

In the early days of modern computing - the 40s, 50s and 60s - computing was a priesthood. Only a few were allowed to commune directly with the machine; all others would give their punched card offerings to the anointed, who would in turn genuflect before their card readers and perform their rituals amid the flashing of lights, the clicking of relays, and the whirring of fans and motors. If the offering was well-received, the anointed would call the communicants forward and in solemn silence hand them printed manuscripts, whose signs and symbols would be studied with fevered brow.

As a noun, design is the named (although sometimes unnamable) structure or behavior of a system whose presence resolves or contributes to the resolution of a force or forces on that system. A design thus represents one point in a potential decision space. A design may be singular (representing a leaf decision) or it may be collective (representing a set of other decisions).

The function of good software is to make the complex appear to be simple.