differential operator

any operator involving differentiation, such as the mathematical operator del ∇, used in vector analysis, where ∇ = i ∂/∂ x + j ∂/∂ y + k ∂/∂ z , i , j , and k being unit vectors and ∂/∂ x , ∂/∂ y , and ∂/∂ z the partial derivatives of a function in x , y , and z