The letter ℘: name and origin? (2017)

I left college with a math degree and a profound antipathy for weird cursive symbols. The one that nearly killed me was the Greek "xi". I couldn't pronounce it, and I couldn't write it with any fluency, and in some of the classes I took it was everywhere.

There is a famous anecdote [0] about Barry Mazur coming up with the worst notation possible at a seminar talk in order to annoy Serge Lang. Mazur defined Ξ to be a complex number and considered the quotient of the conjugate of Ξ and Ξ. (Click link to view 8 lines on top of each other)

[0] https://mathoverflow.net/questions/18593/what-are-the-worst-...