On my UK keyboard, I have a pound symbol (Shift+3=£) , a dollar symbol (Shift+4=$) and a hash key (#)
--------------------------------------------------------------------------------------------------------
'hash'? I've never heard it called that.
'pound', occasionally
'number sign' or 'number', most often and as long as I can remember
'octothorpe', courtesy of the phone company when pushbutton phones came in
... I'm sure there was another I remembered, but not at the moment... AHA - 'sharp' as in C#, the computer language.
Poking around finds a reminder that it is a number sign in #6, and a pound sign in 23#.
And, of course:
# = root prompt
Biting the hand that feeds IT
