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The impication of your third point is that jargon is acceptable if it
is used on a broad basis, or understood on a broad basis. If your definition
of jargon includes recognized process or equipment names, then I agree, but
I think your definition of jargon is too broad.
Jargon, IMHO, is terminology that is ideomatic and is not understood
throughout an entire industry or technology. While a term may be in 'broad
use' throughout an industry in a specific location, if it is not in general
use throughout an industry in all locations it is jargon - it is the same
thing as a local patois or slang.
If a term is used throughout an entire industry or technology and means
the same thing at all locations, then the term can be properly used in a
technical publication - if it isn't, then it is jargon.
I agree whole-heartedly with your first two points. However, I think
your third point is indicative of the basis for this thread - we're lacking
a definition of 'jargon'.