I think it means different things to different people, with the major difference being dependant upon whether you are buying or selling--but more on that later.

A definition for definitions sake might go something like:

Software that's purpose is to gather, store, collate, re-present and communicate information across all job-roll, departmental, divisional and site including country, boundaries within an organisation.

In most cases it will probably not be directly involved in revenue generation, serving a support and control function rather than a core revenue generating role. It can be seen to serve a similar purpose to HR and Legal and Corporate departments within an overall organisation, and it's ROI is equally hard to measure.

In most cases, it will form a net cost burden that must be spread across all areas of the organisations revenue accounts.

Libraries, utilities and tools used in the creation and/or enabling of such intra-organisational (inter-departmental) applications may also be (loosely), so classified.

It may also play some role in the organisations communications with it customers and suppliers in etrading, promotional and communications roles.

A couple of rather cynical takes on the term are:

• In the purchasing department:

  It sounds important, like something we ought to have.

  It can be expected to come with on-going technical support (with the costs spread across many peoples budgets, where it will form a small chunk of a larger single figure, that people will find hard to break down and point fingers).

  With ROI seemingly impossible to gauge, it is unlikely to come back and bite me in the arse.

  If the company profits increase after it's deployment, I can stand up and point to it and claim qudos for having deployed it.

  If profits decrease, it will be exceedingly hard for anyone to point the finger at me and say "It's his fault!".

• From the salesmans point of view, the inclusion of the term "Enterprise" or "Enterprise Edition", means that

  They can charge double for the product up front.

  They can charge double for on-going support and mainenance.

  And if things go wrong within a deployment, it can be attributed to it being wrongly deployed, wrongly used, incomplete coverage or lack of departmental cooperation.