We produce a lot of very detailed and complex legal documents which often
have hundreds of "defined" words in them.

These words are defined at the front of a document in initial cap and bold,
like this "Agreement", "Superior Landlord" etc

Whenever these definitions are referred to throughout the document, all
instances of these defined words should be with an initial capital.

Obviously the problem comes if a document has hundreds of defined words, and
is very long, it is difficult to remember which words have been defined, and
which haven't, and so inconsistencies crop up in the document. Users are
supposed to do a "find and replace" on all defined words, but this can take
some time if there are a huge number of definitions.

What I would like to know is, is there any way that the definitions could be
cross-referenced on a document by document basis, so that whenever an
instance of the definition appears, it automatically changes it to initial
cap?

You could use "Autocorrect" but that is template based, and would not work
on a document by document basis (i'm presuming).

I have a feeling this would require the use of an addin and/or Visual Basic
but at the moment i'm stumped.

Any ideas?