Most English words are polysemantic. It should be noted that the wealth of expressive resources of a language largely depends on the degree to which polysemy has developed in the language.
The system of meanings of any polysemantic word develops gradually, mostly over the centuries, as more and more new meanings are either added to old ones, or out some of them. The general tendency with English vocabulary at the modern stage of its history is to increase the total number of its meanings in this way to provide for a quantitative and qualitative growth of the language;s expressive resources.
The semantic structure of a polysemantic word is treated as a system of meanings. For example, the semantic structure of the noun fire could be roughly presented by this scheme(only the most frequent meanings are given)
Fire, n. – I flame – II instance of destructive burning (e. g. a forest fire); – III burning materials in a stove, fire-place (e. g. There is a fire in the next room. A camp fire); – IV shooting of guns (e. g. to open/case fire); – V strong feeling, passion, enthusiasm (e. g. a speech lacking fire)
It is not in every polysemantic word that such a center can be found. Some semantic structures are arranged on a different principle. In the following list of meaning of the adjective dull one can hardly hope to find a generalized meaning covering and holding together the rest of the semantic structure.
Dull, adj.: 1.Uninteresting, monotonous, boring; 2.Slow in understanding, stupid; 3.Not clear or bright; 4.Not loud or distinct; 5.Not sharp; 6.Not active; 7.Seeing badly; 8.Hearing badly.
Yet, one distinctly feels that there is something that all these meanings holds together. It;s a certain component that can be easily singled out within each separate meaning.