The nabla symbol is used to represent the gradient operator in calculus.
Symbol  Format  Data 

∇  Unicode 

TeX 


SVG 
The gradient operator returns a vector representing the change in a function at a point. The operator is similar to the derivative operator of calculus, the difference being that it operates on functions of higher dimension.
The capital greek letter Δ (Delta) is used in mathematics to represent the change in a variable.