This paper, entrenched in cognitive linguistics, proposes a multidimensional approach to the layering of the lexicon and its semantic organization, explicating the principles of variation and stabilization of lexical networks. Semantic variation is considered as inherent to language structure and driven by common universal cognitive mechanisms which are accounted for by a dynamic conception of meaning construal. Intra-linguistic plasticity of meaning echoes inter-linguistic variation. The discourse level is the seat of meaning construal mechanisms which contribute to the general polysemy of lexical units and to the stabilization of their meaning within a particular utterance. Units appear to be the seat of most variations, within and across languages, because meaning is construed in extremely varied ways according to common mechanisms.