According to the International Union of Pure & Applied Chemistry (IUPAC), the organic chemistry nomenclature is a technique for naming organic chemical compounds in chemical nomenclature. It is presented in the Organic Chemistry Nomenclature (OCN). Guidelines for systematic nomenclature of organic compounds developed by the International Union of Pure & Applied Chemistry and frequently updated. The stem name, prefix, and suffix are the three main components of the IUPAC nomenclature for organic compounds. It is highlighted in this volume that the use of alternative names to draw attention to structural characteristics shared by a number of compounds, or to take into account a particular context does not preclude the use of preferred IUPAC names. The "preferred IUPAC nomenclature" includes the names that are chosen by the institution. In the context of "general IUPAC nomenclature," any name other than a preferred IUPAC name is acceptable as a standard IUPAC name as long as it is unambiguous and adheres to the principles of the IUPAC recommendations herein.