octothorpe

American  

[ok-tuh-thawrp] / ˈɒk təˌθɔrp /

noun

1. a symbol (#) used for numerous purposes, such as before a hashtag, for representing “pound” or “pounds” as a unit of weight or mass, for representing “number” or “numbered,” or as a proofreader's symbol used to indicate the need to insert space.

   Any text following an octothorpe (#) is treated as a comment and ignored.

---

Etymology

Origin of octothorpe

First recorded in 1970–75; octo- ( def. ), after the eight endpoints on the perimeter of the symbol, plus a second element of disputed origin

Example Sentences

Consider the hashtag, the “#” octothorpe symbol, which at any instant can connect social media users with up-to-the-moment news or key words.

From Forbes

Don't worry – almost no one knows it's called an octothorpe, and most of those who do don't call it that.

From The Guardian