Well, I peep inside my dictionary and I observe that it is a reference book, and this reference book has many words, and these words are in an order which is alphabetical, and they have a meaning, or maybe two meanings, and they show other qualities, such as parts of speech, and how these words are pronounced, and their syllabification, whatever that is, and there are details of inflections to consider, which may be irregular, or maybe not, and sometimes a derivation is given, or an etymology, and I don’t know what else.
It seems to me that a citizen may wish to know the plural of dictionary, which is by no means dictionarys, but dictionaries, and I consider the presence of a plural with no singular is more than somewhat a wrong move, but this is just my opinion on the matter.
Furthermore, dictionary is used as a modifier, such as dictionary definition, or maybe dictionary catalogue, or dictionary this, or dictionary that, so dictionary in a dictionary is by no means superfluous, it is essential.
When I say this, I almost forget to mention my dictionary which, in the matter of verbs, has nothing but the present tense, and maybe the past historic, so all of these dictionaries are different, but I am sure many parties complain if dictionary is not in a dictionary, and who is to say this is wrong.