The Kelvin function is also known as the Bessel function of the second kind, and is sometimes referred to as the modified Bessel function of the second kind. It is a mathematical function that is used in a variety of fields, including physics, engineering, and mathematics. The Kelvin function is used to calculate the solutions to certain types of differential equations, and can also be used to model a wide variety of physical phenomena, including heat flow, acoustic waves, and electromagnetic radiation. Other synonyms for the Kelvin function include the Macdonald function, the Weber function, and the Struve function.