What is the official Unicode name for the # character?

What is the official Unicode name for the # character? The answer is “Number sign.”

Unicode assigns each encoded character an official name, and the # character is formally named NUMBER SIGN. Its Unicode code point is U+0023, placing it among the basic ASCII characters used in computing and digital text.

The same symbol has several regional and historical names. In the United States it is often called the pound sign, while “hash” or “hash sign” is common in Britain and many other places. “Octothorpe” is another established name, especially in telecommunications, but it is not Unicode’s official character name.

The symbol’s modern uses extend well beyond numbering. It appears in programming languages, music notation, telephone menus, and social-media hashtags. The hashtag use became especially prominent online, but Unicode’s name reflects the older numbering-related identity of the character.