DCI (Data Context Interaction) is a concept that could help us model our business solutions better. Proposed by Trygve Reenskaug (the creator of MVC), and Jim Coplien (well known expert on OOP and patterns).
DCI aims to have a simplified and more commonsense approach to "Object-Oriented Design". The key observation made is that most object-oriented approaches captures the structural aspects of systems well, they are not so good at effectively handling the behavioral and interaction aspects.
DCI stands for: D: Data, C: Context, I: Interaction.
Most software systems has these three aspects. The structural aspects (Data), Interacts with each other in well defined Contexts.
The main article by Jim Coplien could be found here.
A presentation and interview by Jim Coplien.