octothorpe

[ ok-tuh-thawrp ]

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: hash mark ( def 2 ), pound sign ( def ).

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

Word History and Origins

Origin of octothorpe¹

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