a small "handmade" dictionary is integrated.
What's the size of this dictionary?
Offhand, I'm guessing that the content is duplicated on many other sites, and that is the issue. Note that Google may simply just consider this as "data" (distinct from "content")... and pages that were essentially data-only were hit way back by Mayday.
Unless this dictionary is very large, I agree with Planet13 that if it is a glossary of common terms, you should put everything on one page. I ask about the size, though, because it's not clear that it's large enough to need the alphabetical anchors.
Also, how are you linking to this glossary? If you had articles about each of the terms, then I'd keep them separate and link to them from other articles as footnotes. Many major newspapers use this type of arrangement.
For technical terms on a site, conceivably a single glossary page, with contextual links (from other articles, with anchors leading to individual definitions) might be of use to your users. If you're thinking of these as "important KW-terms", though, your priorities are already such that they'll get you in trouble.
With regard to contextual links... and this may be slightly off-topic, but worth mentioning here... I suggest that you be very careful about (over)using exact match contextual linking just to boost rankings. Many sites I've seen that use contextual links would be better off simply with menus. If it's a small glossary, you might be better off simply with a global "glossary" link, and not try to milk it.