In the US, "#" is most commonly used to mean "number". Its use meaning "avoirdupois pound" is much less common. Yet it's called the "pound sign" (not the "number sign") by all US automated answering systems. That's why it takes old farts like me a second or so to realize what some computer is talking about when it tells me to, "Press the pound sign." I have to mentally translate it to "number sign".

And don't even get me started on "*". It's an asterisk, not a "star".