How do we pronounce this symbol: $\nabla \phi$

Question

I would like to know how to pronounce in English this symbol: $\nabla \phi$.

It is something phi ... ?

Answer 1

The inversed delta is called Nabla. So Nabla phi. See also http://en.wikipedia.org/wiki/Nabla_symbol

Answer 2

it's actually del operator, https://en.wikipedia.org/wiki/Del so it is del phi, in mathematics. nabla article points to that for mathematical usage https://en.wikipedia.org/wiki/Nabla_symbol