Microsoft Java.

Wait it’s not C-Octothorpe?

C-tic tac toe

C++/++

C octothorpe

D♭

cocktothorpe

C-pound

See-octothorpe. Why, how do you say it?

Pfft….C-Pound, duh

Cis. Also Des programming language would be its enharmonic equivalent.

C number

C-noughts-and-crosses-board

c-hash?

Cé dièse

Here we call it C jogo da velha

Or as my mother would call it, after only hearing me mention it a few times: "Sea Shark"

It is often called C Hashtag but it is actually C .Net/(slash) Hashtag

ja mówię ce kratka

Sometimes I call it c sharp but I prefer c hashtag