The titles of lexicographic tools - dictionary, lexicon or encyclopaedia - are normally just names given to them by the publishers, although you may point out certain differences between certain types. At least in the nordic countries the genuine purpose of a dictionary normally is to be giving help by problems with existing texts, the so-called communicative problems. A lexicon serves a narrow field whereas an encyclopaedia serves as a tool for getting knowledge about all fields. Talking about quality in lexicographic works you may point out the lack of quality in the sense of counting errors. But from a metalexicographic point of view the errors are not important. More interesting are those definitions which are correct but not sufficient. The thesis of our paper is that even if you assume a certain completeness, you cannot achieve quality without including a) the type of the potential user - being an expert, a semi-expert or a layman dealing with L1 or L2 - and b) the needs which the reference work wants to fulfil - helping to solve problems in reception, text production, translation, or knowledge achievement. Examples from gene technology and musicology will be given. Our own proposals are based on an Internet dictionary on musical terms, Musikordbogen 2007, which has recently been made accessible.