# Dictionary:Del (∇)

The vector gradient operator. In rectangular coordinates,

where **i, j, k** are unit vectors in the *x, y, z* directions. is the **gradient** of the scalar field U.

The operator , the **Laplacian**, appears frequently:

As an operator on a vector field **V**, is called the **divergence**, and is called the **curl**. Del is also called **nabla** and the **vector operator**. See also Figure C-14 for expressions using del in cylindrical and spherical coordinates.