Words have meaning

Why is it that so many people feel it is acceptable to take words and redefine them for convenience?  Over on Herding Cats, Glen laments the borrowing and redefinition of words by the agile crowd (a crowd of which I part of until a few years back).  I am experiencing one such redefinition:  Enterprise Architecture.

I'll start with my quick and dirty definition of system architecture:  the function and form of a system and how they relate through the system concept.

To me and some others, enterprise architecture is the structure of an system where the scope is the enterprise (e.g., for profit corporation).  The enterprise architecture also describes the enterprise's relationship to outside entities such as capital markets, labor, suppliers, and customers.  Further, it describes how the enterprise system will operate and evolve over time.

To others I know, Enterprise Architecture is defined as the information technology architecture at the scope of the enterprise;  this is another example of IT co-opting a well defined term.  I personally prefer CISR's notion of how enterprise architecture and IT relate:  "A firm’s architecture describes a shared vision of how a firm will operate—thus providing a shared understanding of the role of IT."  In this way IT is a sub-system of the enterprise system.