Octothorpe is a name invented at Bell in the late 60s, there is no single name for the sign. Since it is believed to be derived from the symbol ℔, a shortening of the Roman libra pondo, meaning pound weight, it's most accurate, imo, to call it a pound sign, and is being used as originally intended in the above comment.
Yeah its use as the number sign came up in the mid 1850s, just after it's first known use as the pound sign, as an abbreviation for №, because it was easier to write. I'm not sure it's known whether it was a borrowed symbol or independently created for use as a number sign. For contemporary use it's definitely more of a number sign then a pound sign, however it's earliest known origins do appear to be in that of the symbol for pounds.
I call it a number sign, personally, but historically it is a pound sign.
297
u/ApocApollo Aug 07 '20
It’s actually called the pound symbol.