On: The letter ℘: name and origin? (2017)

[JohnKemeny]

"del" is the only way

[gjm11 → JohnKemeny]

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.)