Subject matter of Lexicology

1. 
   Subject matter of Lexicology.
   

So, the subject-matter of lexicology is the word, its morphemic structure, history and meaning. There are several branches of lexicology. The general study of words and vocabulary, irrespective of the specific features of any particular language, is known as general lexicology

2. 
   Lexicography and its tasks.
   

Lexicography is the study of lexicons, and is divided into two separate academic disciplines. It is the art of compiling dictionaries.[1]
Lexicographers are tasked with defining simple words as well as figuring out how compound or complex words or words with many meanings can be clearly explained.
Theoretical lexicography is the study or description of dictionary organization. In other words, theoretical lexicography analyzes the vocabulary of a particular language and the way the lexicon is arranged. The goal is to create better, more user-friendly dictionaries in the future.
This type of lexicography serves to develop theories about structural and semantic associations among words in a dictionary.
Practical lexicography is the applied discipline of writing, editing, and compiling words for generalized and specialized use in a dictionary. The aim of practical lexicography is to create an accurate and informative reference text that is a reliable asset to students and speakers of the language.

3. 
   Word formation as the main way of enriching the vocabulary of the modern English language.
   

Word-building is one of the main ways of enriching vocabulary. What are four main ways of word-building in modern English? There are four main ways of word-building in modern English: affixation, composition, conversion, abbreviation.
In English grammar and morphology, affixation is the process of adding a morpheme—or affix—to a word to create either a different form of that word or a new word with a different meaning; affixation is the most common way of making new words in English.
Word-composition is another type of word-building which is highly productive. That is when new words are produced by combining two or more stems. Stem is that part of a word which remains unchanged throughout its paradigm and to which grammatical inflexions and affixes are added.
Conversion consists in making a new word from some existing word by changing the category of a part of speech; the morphemic shape of the original word remains unchanged: love — to love, paper — to paper, brief — to brief, work — to work; etc.
Abbreviation is the process of shortening something, usually a word or phrase, or the shortened version itself. “Mr.” is the abbreviation of “mister,” NASA is the abbreviation of National Aeronautics and Space Administration, etc. (hey, that's an abbreviation too