How to pronounce
# in a proper way?
Currently, I know it's used to pronounce "pound" in US English, "hash" in British English, "sharp" for C#--a programming language, and number sign to list items. Not sure if I'm right or not.
Also, I lives in non-English speaking country and many pronounce "hashtag" for this symbol, though I'm suspicious about this.
I'd be glad if you can list more examples about this.
Update: To be clear: The question is about the pronunciation, not how it came from.