[bregma]

I heard as many names for the "\partial" symbol as I had math professors in university. At least they all wrote them the same.

[JohnKemeny]

"del" is the only way

[gjm11]

Except that "del" is also (and I think more commonly) the name for the upside-down Delta used in vector calculus for div, grad and curl.

(I usually say "partial dx by dt" or whatever, which seems OK to me.)