Abstract:  This article is extracted from author’s book—What is Chemistry. In this article, the origin of the Chinese word “Chemistry” is introduced. For example, the first people who defined the word, as well as the meaning of this word. It also demonstrates that chemistry involves the research of chemical substance from three aspects: the component and structure of substance, the synthesis and fabrication of substance, also the description and manipulation of chemical process. The various branches of chemistry are also presented.