per Wikipedia….

In many disciplines a greenfield is a project that lacks any constraints imposed by prior work. The analogy is to that of construction on greenfield land where there is no need to remodel or demolish an existing structure. Such projects are often coveted by engineers.

I love industry terms, especially for those concepts that you otherwise wouldn’t have known there was even a term.

A long-time client recently remarked that my solution delivered "Standardized Customization", confirming how pivotal those design decisions were ten years prior, when I initially conceived much of the architecture that still prevails today in that software.  Core to that success, I believe, was a fundamental understanding that one can not anticipate the changes that will inevitably occur, leading me to focus on flexibility rather than simply a final product.  This, in my opinion, is the key ingredient in any successful implementation, from the smallest features to mission critical solutions - there is no final product. 

The world evolves, thus does business, thus must software.