The word lexicology is derived from the Greek words lexicos - "lexical sign" and logos - "knowledge", and it is a field of linguistics that discusses words and lexical units equal to words, language richness. This book defines the general information about lexicology. Such as: Object, subject, purpose and tasks of lexicology, Systematic study of vocabulary in lexicology, Relationship of lexicology with other sciences, as well as Basic expressions such as structural, systematic, phonetic level, grammatical level, extralinguistic.