So far we have treated meanings of linguistic forms as parts of the external world of which they are symbols. The word 'dog' means the animal dog. The word is said to 'refer to', or 'denote', the thing and the thing is the 'referent' or 'denotatum'. But much of the meaning of language has to do with the attitude of the speaker toward the referent, toward the person spoken to, and toward his own act of speaking. This makes meaning in language a much more complicated matter than just symbols for things and of course much more interesting (...)
In a monolingual dictionary, every word is defined in terms of other words in the language. But if the user does not know the meaning of any of the words, the whole thing is defining in a circle, as we noted in the case of grammatical forms.
(Language and Symbolic Systems, Yuen Ren Chao)