Just a quick question.

It is a pound sign or number sign

# = pound

Also, hash symbol. If the two horizontal lines are actually sloped up, then it's the sharp symbol (musical notation).

Actually its official name is an octothorpe. It was named at Bell Labs when they were designing the touchtone phone to replace the rotary phone. Since they needed 12 buttons for a symmetrical design. They decided to use symbols for the other two buttons. Since the # had several different names, they took to calling it an octothorpe. Unfortunately the name didn't catch on too widely.

they took to calling it an octothorpe. Unfortunately the name didn't catch on too widely.

Yes, I can just hear it now from the voice on the other end giving you information and they say... 'just press the octothorpe to review this information'... no, I can see why it didn't stick !