The Number Sign—#

# has uses other than as the first character in social media hashtags

# number pound hash
Examples of # in several fonts. | Alpha Index to Full Glossary:. # | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | XYZ

Have you used an octothorpe recently? You have if you've typed a hashtag on a social media site. Octothorpe is one name for the number symbol, also called pound sign, number sign, hash or hashtag. 

On a standard U.S. keyboard, the # sign is located on the 3 key, where it is accessed by pressing the keyboard combination Shift+3. It can also be generated with ALT+35 in Windows. It consists of two vertical (or nearly vertical) parallel lines crossed by two horizontal parallel lines.

Despite the relatively recent explosion in popularity of the hashtag on social media, the number sign is most often used in front of a numeral in place of the word "number," such as #1. 

Uses of the # Sign

  • As shorthand for the word "number.Students need to bring a #2 pencil to class to complete quiz questions #1-10.
  • As a proofreading mark designating the insertion of space between lines of text or space between words. Proofreaders insert a # in the text where additional space is needed.
  • As a telephone key, which is typically referred to as the pound key.
  • In computing, the # (here called a hash) designates comments or commands in a programming language, a permalink in a blog and other uses.
  • A series of three # signifies the end of a press release—###
  • In music, the symbol indicates a sharp note.
  • As the previously mentioned designator in social networking known as the hashtag. Hashtags are attached to keywords or phrases to identify messages on a particular topic. For example, #octothorpe.