When to use the word inductance and when to use inductivity?
Inductivity is not an used term in EE

(or at least i have never seen it, if anybody has, feel free to downvote add reference)

My guess would be that the tables you refer to either are very old, and thus contain obsolete vocabulary, or were filled/updated by an operator who did not understand the words he was using. 

The wiktionary definition does not make any sense to me either, unless it is an old term for magnetic permeability.