Quoting Katrien Depuydt depuydt@inl.nl:
I am afraid that even the list of lemmata (without the entries) is considered to be intellectual property, at least it is in the Netherlands and Belgium. I would ask permission from the editors of each lexicon.
This is interesting. Would it be too troublesome of me to ask what precisely is meant by "is considered"? The publishers consider it so? Common perception? It is explicitly enshrined in copyright law to be so? It has been tested in court and held up?
(This is a genuine question: so much of even expert legal opinion on these matters can be in doubt unless the claim has been tested. On the other hand, if you work for a college or similar institution, you will no doubt be under strict instructions to cover your back, so the unsatisfactory answer is that you should consider something under copyright and requiring permission unless it is absolutely unmistakably the case that it is not...)
Yours continuing to seek disambiguity where there probably is none,
G