How do we pronounce this symbol?

I would like to know how to pronounce in english this symbol $\nabla \phi$ It is something phi ... ?

thank you

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del phi? –  Daniel R May 12 '14 at 11:51
If you know the context, you can also say "grad phi" (if in the context of gradient), or it could be used in the context of curl or divergence. That's a more "informed" pronunciation that tells you more than just plain notation. –  orion May 12 '14 at 11:56
Thanks to @Daniel, now I know what to call oracles in the future! –  Hurkyl May 12 '14 at 12:08
Detexify can sometimes help with this kind of question: detexify.kirelabs.org/classify.html –  Phira May 12 '14 at 12:30
@Phira What an awesome site! That should be stickied somewhere (and probably is already) –  Mathias711 May 12 '14 at 12:39

1 Answer

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

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thank you very much :) –  OSryx May 12 '14 at 11:52
Welcome, good question! –  Nicky Hekster May 12 '14 at 11:53
Is it also called nabla when dealing with finite differences? I have always called it "nabla" in vector analysis, but I have a doubt for other uses. –  jca May 12 '14 at 14:03
@Jean-Claude Arbaut: nabla is a name of “∇” symbol (cf. equals sign – “=”, times sign – “×”). Del is a name of the operator in vector analysis. The thing with finite differences is not del, but if the symbol is “∇”, then it’s nabla. –  Incnis Mrsi Dec 13 '14 at 10:34
@IncnisMrsi This makes sense. In physics, though, we always spelled it "nabla phi", not "del phi", but it may be a french usage. Thank you anyway. –  jca Dec 13 '14 at 12:11