All this is saying is that ISO 9000:2000 is a reference document but necessary to the standard. Think of ISO 9000 as you did the old 'definitions' document. It is, in a way, a link. One may say it is a foundation. The title of ISO 9000 is: QUALITY MANAGEMENT SYSTEMS - FUNDAMENTALS nad VOCABULARY
Definition 1. of, pertaining to, or prescribing a law, standard, or norm, esp. with regard to correctness in speaking, writing, or behavior.
Crossref. Syn. * standard
*Definition 1. the act or process of referring.
* *Synonyms * referral (1)
* *Crossref. Syn. * relation
* *Definition 2. an allusion.
* *Synonyms * mention (1) , allusion
* *Definition 3. a source of information.
* *Example * She is a good reference on computer matters ; We go to the library to look up references.
Bottom line is you should be looking at ISO 9000, ISO 9001 and ISO 9004 as a group.
The reality is most companies buy and consider ISO 9001 and that's it. Few buy and read ISO 9000 and ISO 9004 as well which I personally believe is a very bad business practice.
As it was explained to me (by our registrar) during transition training - The normative reference ISO 9000:2000 (fundamentals/vocabulary) must be used in conjunction with the standard itself - meaning the terminology specified is NOT open for interpretive discussion.