Number Sign


The term “number sign” refers to the symbol “#” commonly used to denote numbers, pounds in weight, or as a hashtag in social media. For instance, when used for numbering, it may appear as “#1” to indicate number one. In social media, hashtags help to categorize content by linking relevant posts, such as #technology for technology-related posts.

Key Takeaways

  1. Number Sign (#), commonly known as Hashtag, is a metadata tag in social media that helps users identify messages on a specific topic or theme.
  2. By clicking on or searching for a Number Sign followed by a keyword, users can find all the relevant posts tagged with that keyword in a chronological order, promoting organized communication and content discovery.
  3. In programming languages, the Number Sign can serve as special syntax, comments, or directives, depending on the language, increasing the versatility of the symbol in numerous contexts.


The number sign, also known as the hashtag or pound sign, is an important technology term because it serves multiple purposes in different contexts.

In programming languages, it often represents the start of a comment, allowing developers to leave notes or explanations within their code.

On social media platforms such as Twitter and Instagram, the number sign has evolved into the hashtag, which is used to categorize and tag content, making it more discoverable for users with similar interests.

In telecommunications, the number sign is used on phone and fax machines as an input symbol, initiating specific functions like ending a message or starting a multi-way call.

Overall, the number sign plays a crucial role in streamlining communication and organizing digital content across various technology platforms.


The Number Sign, commonly recognized as the hashtag symbol (#), serves various purposes in the realm of technology and communication. Initially, the symbol was widely utilized in the programming world, as it plays a significant role in several coding languages. This enables a more structured and organized approach to scripting, as the Number Sign often denotes comments within the source code.

By inserting this character, programmers can annotate their code with helpful explanations or reminders without affecting the actual execution of the script. Apart from that, the Number Sign is often employed in mathematics and engineering applications to represent a numeric value or even as a symbol for sharp notes in music notation. In recent years, the Number Sign has gained substantial popularity on social media platforms—primarily Twitter—where it functions as a “hashtag.” This particular use facilitates the process of aggregating, categorizing, and searching for specific topics, trends, or ideas on social media.

By placing the Number Sign before a keyword or phrase, without spaces, users can create tags that link their posts to a broader conversation in the online community. Consequently, this aids users in discovering and interacting with like-minded individuals who share similar interests. As a result, the Number Sign has evolved into a multi-functional tool for users across various domains, proving its versatility and adaptability in the digital age.

Examples of Number Sign

The Number Sign, commonly referred to as the hashtag (#), is a metadata tag widely used on social media platforms and other online communication tools. Here are three real-world examples:

Social Media Campaigns: On social media platforms like Twitter, Instagram, and Facebook, hashtags are used to categorize posts and make them easily discoverable. For example, during the “Ice Bucket Challenge” campaign to raise awareness for ALS, people used the hashtag #IceBucketChallenge when posting their videos and nominating others.

Live Events: Organizers of conferences, workshops, or other events often create a dedicated hashtag for the event, enabling attendees to discuss and share information in real-time. For example, during the annual technology conference South by Southwest (SXSW), participants may use the hashtag #SXSW to post updates, photos, and engage with other attendees.

Breaking News and Social Movements: Hashtags are often associated with breaking news events or social movements, allowing users to follow updates and get involved. For example, during the Arab Spring uprisings, hashtags like #ArabSpring or #TahrirSquare were used to aggregate news, images, and opinions from people on the ground. Similarly, in the fight against racial inequality, the hashtag #BlackLivesMatter has played a critical role in drawing attention to the movement and facilitating conversations around it.

FAQ Section: Number Sign

What is a Number Sign?

A Number Sign, also known as “hashtag” or “pound sign”, is a symbol used primarily on social media platforms to categorize content by theme or topic. The symbol itself looks like this: #

What is the purpose of a Number Sign in technology?

In technology, the Number Sign has various uses, such as designating a comment in programming languages, categorizing messages on social media platforms, and invoking commands in programming language interpreters.

How do I use a Number Sign on social media?

To use a Number Sign on social media, simply type the symbol (#) followed by a relevant keyword without spaces. This will create a clickable link, allowing users to discover other content associated with the same topic. For example: #technology

Do all social media platforms support Number Sign usage?

Most popular social media platforms, such as Twitter, Instagram, and Facebook, support the use of Number Signs to categorize content. However, the implementation and functionality may vary between platforms.

Can Number Signs be used in programming languages?

Yes, Number Signs can be used in programming languages, often to indicate a comment, which is a line of text that is not executed as code. In other languages, a Number Sign is used to invoke commands in the interpreter. The usage of Number Sign varies depending on the programming language.

Related Technology Terms

  • Hash symbol
  • Octothorpe
  • ]),

  • Pound sign
  • Phone keypad
  • Hashtag

Sources for More Information


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