Nonlinear dynamics can be defined as the study of complex systems in which the output is not proportional to the input. There are many synonyms for nonlinear dynamics, such as chaos theory, complex systems theory, and dynamical systems theory. These terms all describe the same field of study, which focuses on understanding the behavior of systems that are not deterministic or predictable. Nonlinear dynamics is used to understand a wide range of phenomena, including weather patterns, biological systems, and financial markets. By studying nonlinear dynamics, researchers can gain insights into the complex behaviors and interactions that govern many real-world processes.