# How do you pronounce (partial) derivatives? [closed]

I am not an English speaker that is why I asked this question. In addition, I think english.stackexchange.com is not the proper place to ask this because (I am so sorry) I don't think most of them know mathematics deeply.

How do you pronounce the following derivatives in English?

1. $\frac{\textrm{d}y}{\textrm{d}x}$
2. $\frac{\textrm{d}^2y}{\textrm{d}x^2}$
3. $\frac{\partial y}{\partial x}$
4. $\frac{\partial^2 y}{\partial x^2}$
5. $\frac{\partial^3 y}{\partial x^2\partial z}$

Feel free to edit the tag if it has been chosen incorrectly.

For example, is it correct if I pronounce $\frac{\textrm{d}y}{\textrm{d}x}$ as "dee wai over dee eks"?

This is how I personally pronounce them:

1. I pronounce it either "dee wai over dee eks" or simply "dee wai dee eks".
2. I occasionally pronounce it as "dee squared wai over dee eks squared", but more often I just refer to it as "the second derivative of y with respect to x".
3. "Partial of y with respect to x." Very occasionally as "del wai del eks".
4. As with 2, I usually just call this "the second partial of y with respect to x".
5. "del cubed y over del $x^2$ del z", but if we have $y=f(x,z)$, I'd much prefer referring to it as $f_{zxx}$.
• del means something different – Elements in Space Jan 5 '13 at 14:05
• 3. I would say "partial wai partial eks" – user7530 Jan 6 '15 at 20:18

3. $$\frac{\partial y}{\partial x}\rightarrow\text{day wai, day eks}$$

5. $$\frac{\partial^3 y}{\partial x^2\partial z}\rightarrow\text{day cubed wai, day eks squared, day zee}$$

6. $$\nabla F\rightarrow\text{del eff}$$