(a) Most dictionaries are also declension-aries,
(b) I really like your word declension-ary,
and (c) Declension is what you do to nouns and is analogous to conjugation of verbs, which I think is what you are looking for :-)
(a) Most dictionaries are also declension-aries,
(b) I really like your word declension-ary,
and (c) Declension is what you do to nouns and is analogous to conjugation of verbs, which I think is what you are looking for :-)