Research area classification is the process of categorizing different fields of study or disciplines based on their subject matter and methods of inquiry. This classification system helps researchers, policymakers, and funding agencies identify and organize research areas to better understand the diverse landscape of scientific inquiry. There are several different classification systems used in research, including the widely used Web of Science categories, the Research Subject Classification (RSC) system, and the Field of Science and Technology Classification (FOS). These systems typically divide research areas into broad categories such as natural sciences, social sciences, humanities, engineering, and health sciences, and further subdivide them into more specific fields such as physics, psychology, literature, civil engineering, and medicine. Research area classification is important for identifying trends and patterns in scientific research, tracking the growth and development of specific fields over time, and facilitating collaboration and interdisciplinary research. It also helps researchers and policymakers allocate resources and funding to areas of study that are deemed most important or promising.