The research on vocabulary is the overall research including words and meanings and their relationships. Foreigners who study Chinese should know that lexicology is the subject that research words and vocabulary. Generally speaking, there are four classifications of the lexicology that the foreigners should know when they study Chinese. The general lexicology researches the general theories of words and vocabulary. It is the theory part of the lexicology. The individual lexicology regards certain language as the subject like Chinese lexicology and English lexicology.

Besides, the history lexicology aims at studying the development and changes of certain vocabulary system, which is called synchronic. When you study in Chinese program in China, teachers may tell you that the descriptive lexicology is about the conditions and features of vocabulary in certain period of time, which is called diachronic. In all, foreigners who study Chinese should know that the synchronic study forms history comparison lexicology and the diachronic study forms descriptive lexicology. Besides, there are some small branches produced in vocabulary study like etymology, idiom research and so on.