1. lexicology is the “science of the word”, a subbranch of linguistics dealing with vocabulary.
A word is a minimal free form of language which has given sound and meaning （lexical and grammatical) and syntactic function(句法功能） The Characteristics of the Basic Word Stock (1) All national character (全民性)
（2）stability (稳定性) (3) productivity（能产性） (4) polysemy（多义性） (5) collocability（搭配性）
2. Methods of word-formation：In English, there are various ways of word-formation such as affixation, conversion, compounding, blending, backformation, shortening, Reduplication， etc. Motivation deals with the connection between name and sense. 词的理据指的是事物和现象获得名称的依据.
1. Onomatopoeic Motivation (Phonetic motivation) (拟声理据) 2. Motivation by meaning (Semantic Motivation) (语义理据) 3. Logical motivation ( 逻辑理据)
4. Grammatical motivation ( 形态理据或语法理据)
3.Types of Word Meaning: 1.1 Grammatical meaning(语法意义)refers to that part of meaning of the word which indicates grammatical concept or relationships such as the word class, singular and plural forms of nouns, tense meaning of verbs and their inflectional forms. Lexical meaning(词汇意义) is the meaning of an isolated word in a dictionary. Conceptual meaning概念意义
Associate meaning(关联意义) is the secondary meaning supplemented to the conceptual meaning. Associative meaning comprises four types: connotative meaning内涵意义, stylistic meaning, affective meaning, and collocative meaning搭配意义.
4. Purpose of Componential Analysis：By digging out these traits and classifying them, we may know clearly their relationship between their synonymous pairs. So component analysis is a useful and revealing technique for demonstrating relations of meaning between words.
Componential Analysis(语义成份分析), according to Leech, is the process of breaking down the word sense of a word into its minimal components. Sememe (义素) is such smallest sense unit in the semantic system of a word.
5. Context is the necessary condition of pragmatic meaning 语用意义of words.
The basic features of pragmatic meaning: 1) Primary meaning adhesive（忠实原意） : Each word must be adhesive to its primary meaning . 2）Personal experienced ：In most cases, the use of a certain word will recall a lot of speaker’s association. 3）Unstable: In order to suit different context. it is necessary to extend or shorten the overtone of the word conceptual meaning. 4）Temporary： Sometime the speaker adjust the conceptual meaning to serve the context. 5)语境的共生性。语用意义在运用的过程中必须和语境共生共灭。
6. Context refers to the condition or the background how a word is used. It can be divided into linguistic context and non-linguistic context.（语言语境和非语言语境）Context is the necessary condition of pragmatic meaning of words.
Linguistic context refers to grammar , collocation of the vocabulary, passage, and sentence;
Non-linguistic context refers to the factors beyond language. It is related with time , place, relationship between participants, their understanding of the events and other social surrounding.多指语言运用中的社会环境
So its appropriateness depends on culture and social situation.
7. Synonymy同义词：“Words different in sound and spelling but most nearly alike or exactly the same in meaning. Synonyms share a likeness in denotation as well as part of speech, as with enormous and immense.
8. Hyponymy deals with the relationship of semantic inclusion. It refers to the relationship which obtains between the genus (general lexical item)and the species(specific lexical items). The general lexical item is called the superordinate(上义词).
The specific words are known as hyponyms(下义词) or subordinates .
9. Antonymy 反义词is concerned with semantic opposition. Antonyms can be defined as words which are opposite in meaning. They are a variety of “oppositeness”.
10. Polysemy 多义词is a common feature peculiar to all natural languages. This is particular true of highly developed languages like English .
When the same symbol is used to express different phenomenon, the result is polysemy.
11. Homonymy 同形异义关系：Homonyms are generally defined as words different in meaning but identical both in sound and spelling.
(A) Perfect homonyms(完全同形同音异义词)(B) full homonyms (实足同形或同音异义词) (C) Homophones (同音异义词)(D). Homographs (同形异义词
12. There are probably two major factors that cause changes in meaning词义演变的原因：The changes of meaning may be caused by internal factors within the language system. With the advancement of science and the improvement of people’s acknowledgment and understanding of the world , some words embrace broader meaning. Changes take place through the process of extension, degradation降格, elevation , narrowing, and transfer.
Extension refers to a process by which a word with a specialized sense is generalized to cover a broader or less definite concept. Extension : also known as generalization, refers to the widening of meaning. Elevation: or amelioration which refers to the process of words rising from humble beginning to positions of importance.
Degradation refers to a process by which a word of reputation slides into a pejorative use.
Degradation: or pejoration is the opposite of semantic elevation. It is a process whereby words of good origin fall into ill reputation or non-affective words come to be used in derogatory sense. Narrowing: refers to a process by which a word of wider meaning acquires a specialized sense. Narrowing : also called specialization, is the opposite of widening. It is a process by which a word with a wide meaning acquires a narrower or specialized sense.
13. 词的搭配：习惯上讲二个或两个以上的词的组合叫做搭配。 反映了词语之间的共线关
系。Firth uses a less technical expression for this term,it is “the mutual expectancy of words,” He said that “You shall know a word by the company it keeps”. 搭配的理据：指的是所表达得事物或现象获得名称的依据，由此而说明搭配的事物或现象的名称之间的关系。
Collocation must satisfy a certain syntactic ,idiomatic and pragmatic purpose.
Chomsky handles collocation within the framework of grammar(or syntax) . That is based on the grammatical rules and the semantic features of lexical items.
14. Characteristics of idioms:：Being phrases or sentences, idioms each consist of more than one word, and a semantic unity. The individual element loses its respective literal meaning and identity. Likewise, the part of speech of each element is no longer important.
1 ) Semantic unity: In fact, the semantic unity of idioms is reflected in the illogical relationship between the literal meaning and the meaning of the whole idiom,which is often semantically inexplicable.
2）Structural stability: Unlike free phrases, the structure of an idiom is to a large extent, unchangeable. That is , the constituents of idioms cannot be replaced
3 ） Idioms are grammatically unanalysable and semantically inexplicable
英语成语分类According to their expressive function, we can divide them into figurative idioms; phrasal verbs; English Proverbs; and English Slang and English twin words.
15. Context helps define reference. Context helps establish and accumulate presuppositions. Context helps hearer detect conversational implicature.
