Octothorpe mindblown
We don’t really give a lot of thought to the names of symbols. For instance, does anything know what the shift+number keys on your keyboard are, from 1 to 0? We have the exclamation sign, percentage, ampersand, asterisk, and everything else, we don’t care enough to learn about. But there is one symbol, #, that has changed its name over time.
Back in our day, we called # the pound sign or number sign. Today, they’re “hashtags” thanks to social media. The technical term for this symbol is octothorpe, and it also denotes sharp musical notes. As for the infinite symbol, ∞, it’s called a lemniscate.