cnoidal

Meaning

Adjective

• Describes a travelling wave whose amplitude is constricted; e.g. a wave in shallow water.

Origin

• Coined by Korteweg and de Vries in their paper in Philosophical Magazine (1895, series 5, vol. 39, pp. 422-443) to describe a class of solutions to the KdV equation which involve a Jacobi elliptic function. The Jacobi elliptic function involved is commonly written as $cn(x|m)$, and the term cnoidal was designed to be analogous to sinusoidal, the word describing waves which involve the sine function.