
The # Symbol Is Officially Called an 'Octothorpe'
The '#' symbol's formal name is 'octothorpe' — 'octo' referring to its 8 line endpoints. It is also known as 'hash', 'pound sign', and 'number sign'. Other languages have creative names for it: 'snail' in Italian, 'monkey tail' in Dutch, 'elephant trunk' in Finnish, and 'little duck' in Greek. Twitter popularized 'hashtag' after 2007.