Surprisingly, the pound sign/octothorpe does not have the same storied history of use that other conventional punctuation marks have, such as the period or question mark. Some of the earliest known uses of the symbol date back from traders’ logs in southern Europe in the 17th century, where they used a funky version of the symbol as shorthand for the word pound, as in weight. Historians surmise that the hashtag was borne from a very messy scrawling of ℔, which stood for weight in pounds (fun fact: lb stands for libra pondo – Italian for weight in pounds). When traders and bookkeepers would hastily write ℔ in their records in cursive, it’d end up looking like the letters had been crossed out not once, but twice.