Partial differential equations (PDEs) are mathematical equations used to describe phenomena in which multiple variables are involved and are constantly changing. Some synonyms for the term PDEs include Partial derivatives, Multivariable calculus, and Nonlinear equations. PDEs have a wide range of applications in various fields of science and engineering, including physics, chemistry, economics, and computer science. PDEs are used to model complex systems and predict their behavior, making them an indispensable tool for scientific research. In summary, PDEs are an essential branch of mathematics with a broad range of applications and synonyms that capture different aspects of their complexity.