The article makes an attempt to determine the nature of representation of meanings in the semantic space of the lexicon by revealing the content of semantic structures of polysemantic words. It presents the results of many years of searching in the field of semantic commonality of the meanings of polysemants, which are called “general meaning”. It has been demonstrated that meaning is a diffuse configuration of semantic components formed at the time of speaking and adapted to a specific linguistic and extralinguistic environment. The paper profounds a hypothe-sis that the semantic network of the polysemantic structure of words as a multilevel configuration of meanings is fixed by a dominant invariant meaning. An analysis of the English substantive key using the empirical invariant-component method is presented in evidence of the advanced hy-potheses. As follows from this analysis, the semantic metaphorical clusters of meanings of this word and its lexical invariant have been identified as a set of basic dominant components that form the semantic kernel of the word. The results of the study allow for the conclusion that in order to preserve the semantic integrity of the structure of a word, the semantics of a word is as-sociated with its lexical invariant.Keywords: mental and speech lexicon, polysemantic word, lexical cluster, lexical invariant, semantic net-work, semantics, meaning.