1. The subject of Lexicology and the main lexicological problems

Semantic structure of a word.
The semantic structure is an interrelation and interdependence of all its lexico-semantic variants. It’s determined not only by a number of its lexico-semantic variants, but also by their type. The semantic structure is a flexible category, it is changing with a development of the language. As a polysemy semantic structure exists only in language not in speech. Paradigmatic relation defines the word meaning through its interrelations with other members in dictionaries with one of the subgroup of vocabulary units. Syntagmatic relations defines the word meaning in the flow of speech in different combinations through varies context. There is no single semantic component common to all lexico-semantic variants. Every variant has something in common with one of the other. Every meaning in language and every difference in meaning is singled either by the form word itself or by context. Lexico – grammatical variants of a word are its variants characterized by paradigmatic all morphological peculiarities, valency, different syntactic functions, very often belong to different lexico-grammatical groups of the same part of speech. In the semantic structure of the word “youth” lexico-grammatical variants can be distinguished: 1) uncountable noun (friend of one’s youth) 2) countable personal noun (as a young man) 3) as a collective noun (young men and women). There are 2 approaches to polysemy: diachronic and synchronic. If polysemy is viewed diachronically it’s understood as growth and development or as a change in the semantic structure of the word. It means that a word may retain the previous meaning and at the same time acquire one or several new ones. According to this in the semantic structure of the word 2 types of meaning can be singled out: primary and secondary. FE: the word “table” today has 9 meanings. Synchronically polysemy is understood as the coexistence of various meaning of the same word at a certain historical period oh language development. The same word “table” most of all occurs as “an article of furniture” it‘s the central meaning of the word, other meanings are marginal. Central meaning occurs widely in different context, while marginal is only in certain context.