Abstract: Lexicology refers to all the words in English language. In this essay, I will focus on the practicality of Lexicology and why we English learners should learn it. A good knowledge of morphological structures of English words and rules of word-formation will help learners develop their personal vocabulary and consciously increase their word power. The information of the historical development and the principles of classification will give them a deeper understanding of word-meaning and enable them to organize, classify and store words more effectively. The understanding and their sense relations will gradually raise their awareness of meaning and usage, and enable them use words more accurately and appropriately. A working knowledge of dictionaries will improve their skills of using reference books and raise their problem-solving ability and efficiency of individual study. In the essay, I will study the meaning of learning Lexicology from learners and also the educators. Explore the Lexical reasons of Polysemy and what dose it matter with learners, how Lexicology can help learner understand the meanings and use them properly. Lexicology is not just a useless, hard course. It has its useful meaning for learners in the social work.
Key words: Lexicology, polysemy, vocabulary, The term Lexicology was borrowed from the French word lexicologie, which contains two morphemes: one is Greek lexicon, meaning ‘wordbook’ or ‘vocabulary’; the other is French logie, meaning ‘the study or science of’. So the literal meaning of the term is ‘the science of words’. Lexicology is the part of linguistics which studies words, their nature and meaning, words' elements, relations between words (semantical relations), word groups and the whole lexicon. The probe into the English lexicology starts late in China even in Europe and America for subjective reasons and also objective reasons. People always think that