Del, or
nabla, is an
operator used in mathematics, in particular, in
vector calculus, as a
vector differential operator, usually represented by the
nabla symbol ∇. When applied to a
function defined on a
one-dimensional domain, it denotes its standard
derivative as defined in
calculus. When applied to a field (a function defined on a multi-dimensional domain), del may denote the
gradient (locally steepest slope) of a
scalar field (or sometimes of a
vector field, as in the Navier–Stokes equations), the
divergence of a vector field, or the
curl (rotation) of a vector field, depending on the way it is applied.
