An Etymological Dictionary of Astronomy and Astrophysics

A differential → operator, denoted ∇² = ∇.∇,
which is the sum of all second partial derivatives of a dependant variable:

∇²≡ ∂²/∂x² + ∂²/∂y² + ∂²/∂z², in Cartesian coordinates.

It has numerous applications in several fields of physics and mathematics. Also called Laplace operator.

See also: Named after → Laplace.