Data-Oriented Design, or DOD for short, seeks to maximize efficiency by laying out data in such a way that their processing is as streamlined as possible. This is often against the usual object-based principles that naturally lead to grouping the information accordingly to the user-domain entities that it models. Consider for instance a game where large quantities of particles are rendered and moved around.

Follow up: http://bannalia.blogspot.lu/2015/09/c-encapsulation-for-data-oriented.html