The story
Named after German mathematician Peter Gustav Lejeune Dirichlet (1805–1859), who made significant contributions to the theory of Fourier series.
Etymology from Wiktionary, CC BY-SA 4.0.
Dirichlet energy
Today it means: A quadratic functional which, given a real function defined on an open subset of ℝⁿ, yields a real number that is a measure of how variable said function is. Full definition →