Language is often a bridge between cultures, but sometimes it acts as a confusing crossroad. Few linguistic quirks illustrate this better than the term "pound sign." Depending on which side of the Atlantic Ocean you reside, hearing the phrase "pound sign" will conjure one of two distinct visual images: the elegant, curved currency symbol for the British pound sterling (£) or the grid-like hash symbol used on telephones and social media (#).

This dual identity is more than a mere curiosity; it is a source of genuine confusion in international banking, software development, and daily communication. Understanding why these two symbols share a name requires a journey through Roman history, the evolution of bookkeeping, the birth of modern telecommunications, and the logic of computer character sets.

The Currency Pound Sign: History and Usage of £

The symbol £ is universally recognized as the mark of the British pound sterling (GBP). However, its influence extends far beyond the United Kingdom, appearing in various forms across several nations that have historical or economic ties to British currency.

The Latin Roots of Libra

The origin of the £ symbol lies in the Roman unit of weight: the libra. In Latin, libra pondo translates to "a pound by weight." This phrase is the ancestor of both the unit of mass (the pound, abbreviated as "lb") and the unit of currency.

When the pound was established as a currency in early England, it was literally defined as a pound's weight of silver. Consequently, the capital letter "L" became the logical choice to represent this value. Over centuries of handwriting, scribes began adding a horizontal crossbar (or sometimes two) to the letter "L." This was a common medieval practice to indicate that the letter was being used as an abbreviation or a specific symbol rather than a part of a word.

By the late 17th century, the symbol had stabilized into the £ we recognize today. The Bank of England museum houses a cheque dated January 7, 1661, which features a clearly recognizable £ sign, proving that the symbol was already in formal commercial use centuries before the digital age.

One Bar or Two: The Style Debate

A common point of confusion is whether the pound sign should have one horizontal bar (£) or two (₤). Historically, both versions were used interchangeably. In the 18th and 19th centuries, it was largely a matter of the typographer's preference or the style of the specific font being used.

Modern standardization has largely settled on the single-bar version. The Bank of England has used the one-bar style exclusively on its banknotes since 1975. In the world of computing, the Unicode standard treats them as stylistic variants of the same character (U+00A3), though the two-bar version is often associated with the former Italian Lira (₤), which also derived its name from libra.

Global Currencies Using the £ Symbol

While the British pound sterling is the most famous user of the symbol, it is not the only one. Many territories and nations use the £ sign for their own pounds:

  • The Egyptian Pound (E£)
  • The Syrian Pound (S£)
  • The Lebanese Pound (LL)
  • The Gibraltar Pound
  • The Falkland Islands Pound

In international finance, to avoid any possibility of error, the symbol is often bypassed in favor of ISO 4217 codes like GBP, EGP, or SYP.

The Number Sign: How # Became the Pound Sign in North America

If you travel to the United States or Canada and an automated phone system asks you to "press the pound sign," no one expects you to look for a currency symbol. Instead, you are expected to press the # key. To most of the rest of the world, this is the "hash," the "number sign," or increasingly, the "hashtag."

The Evolution from "lb" to

Remarkably, the # symbol shares the same ancestor as the £ symbol: the Roman libra pondo. In the United States, during the 19th century, the abbreviation for the unit of weight "lb" was often written with a horizontal bar across the top to indicate it was a contraction.

As clerks and merchants wrote this "lb" with a bar quickly and repeatedly, the letters began to blur. The vertical strokes of the "l" and the "b" combined with the horizontal bar, eventually morphing into the four-stroke grid we now call the hash. By the time the typewriter was invented in the late 1800s, this symbol was included on keyboards as a shorthand for weight. If placed after a number (e.g., 5#), it meant "five pounds." If placed before a number (e.g., #1), it meant "number one."

The Bell Labs and the Octothorpe

The widespread adoption of the term "pound sign" for the # symbol was cemented by the telecommunications industry. In the 1960s, engineers at Bell Labs were developing touch-tone dialing. They needed two special symbols to flank the zero on the keypad. They chose the asterisk (*) and the square grid (#).

According to telecommunications lore, the engineers felt the symbol needed a more formal, technical name than "pound sign" or "hash." An employee named Don Macpherson reportedly coined the term Octothorpe. The "octo-" prefix clearly referred to the eight points on the symbol's ends. The "thorpe" part remains a mystery—some say it was named after the athlete Jim Thorpe, while others claim it was an Old English word for a village. Despite their efforts, "octothorpe" never caught on with the general public, and "pound sign" remained the standard American term.

The Rise of the Hashtag

In 2007, a technologist named Chris Messina proposed using the # symbol on Twitter to group related messages. He called these "channels." Because of the symbol's name in computer programming (the hash), the term "hashtag" was born. This global digital phenomenon has done more to standardize the name "hash" than any dictionary ever could. Even in the U.S., younger generations are increasingly likely to call # a hashtag rather than a pound sign.

Why the Confusion Exists: The Linguistic Divide

The confusion between £ and # is a classic example of regional linguistic divergence.

  1. United Kingdom and Commonwealth: In the UK, Australia, and New Zealand, the word "pound" is so deeply synonymous with their currency and history that applying it to a mathematical symbol like # feels unnatural. To them, # is a "hash" or a "number sign."
  2. United States and Canada: Because the U.S. uses the dollar ($), the word "pound" was free to be used as a description for the weight-derived symbol #. For a long time, Americans had little daily interaction with the £ symbol, so the name "pound sign" was uniquely reserved for the # key.

In Canada, the situation is particularly fluid. Due to its proximity to the U.S. and its historical ties to the British Crown, both meanings are understood, though "number sign" is often preferred in formal contexts to avoid ambiguity.

Technical Specifications: Encoding the Pound Signs

For developers, designers, and data scientists, the difference between these signs is not just linguistic—it is digital. Using the wrong code can break a database or display garbled text on a website.

Unicode and ASCII

  • The Currency Symbol (£): In Unicode, this is U+00A3. In HTML, it can be represented by the entity £.
  • The Number Sign (#): In Unicode, this is U+0023. In HTML, it is simply # or #.

The history of ASCII (American Standard Code for Information Interchange) reveals why this confusion persisted into the computer age. In the early days of 7-bit computing, there were only 128 available slots for characters. Many countries created their own national variants of ASCII.

The British standard (BS 4730) replaced the # symbol (position 0x23) with the £ symbol. Consequently, if you sent a document from a UK computer to a US computer in the 1980s, all the currency signs might suddenly turn into hashes, or vice versa. This "Mojibake" (character corruption) was a major headache until the universal adoption of Unicode (UTF-8).

Programming and Syntax

The # symbol is a workhorse in the world of programming:

  • Python/R/Perl: It is used to denote comments in the code.
  • CSS: It is used to identify "id" selectors or to define hexadecimal colors (e.g., #FFFFFF for white).
  • C/C++: It is used for preprocessor directives like #include.
  • Unix/Linux: The "shebang" (#!) at the start of a script tells the system which interpreter to use.

The £ symbol, by contrast, is rarely used in actual code syntax and is almost exclusively treated as "data" or a string literal representing money.

How to Type the Pound Signs on Any Device

Depending on your hardware and keyboard layout, finding these symbols can be tricky. Here is a quick reference for the most common systems.

Typing the Currency Symbol (£)

  • Windows:
    • If you have a numeric keypad: Hold Alt and type 0163 or 163.
    • On a standard US keyboard without a keypad: You may need to use the "Character Map" or switch to a "United Kingdom" keyboard layout in settings.
  • Mac:
    • Press Option + 3. This works on most US and International English layouts.
  • Linux:
    • Press Ctrl + Shift + U, then type 00A3 and press Enter.
  • Mobile (iOS/Android):
    • Open the numeric keyboard and long-press the dollar sign ($) or the "123" submenu to find the £.

Typing the Number/Hash Symbol (#)

  • Windows/Mac/Linux:
    • On a US layout: Press Shift + 3.
    • On a UK layout: Press the dedicated # key, usually found near the Enter key.
  • Mobile:
    • Directly available on the primary symbols page of any mobile keyboard.

Avoiding Miscommunication in Professional Contexts

When working in an international environment, using the term "pound sign" without context is a recipe for error. To ensure clarity, follow these best practices:

  1. Be Specific: Instead of "pound sign," say "British pound symbol" or "the hash/number sign."
  2. Use ISO Codes: In financial documents, use "GBP" instead of £. It is unambiguous and recognized by every bank in the world.
  3. Visual Aids: If you are writing instructions for a software interface, use the actual glyph (e.g., "Click the # icon") rather than the name.
  4. Consider the Audience: If your readers are primarily in the UK, "pound" means money. If they are in the US, "pound" means the phone key. Adjust your terminology accordingly.

Summary

The "pound sign" is a fascinating example of how history and geography can split a single term into two distinct meanings. Whether it is the £ rooted in the weight of Roman silver or the # born from the rapid scribbling of ledger entries, both symbols are essential to our modern world. One facilitates global commerce and represents the strength of the British economy, while the other organizes our digital conversations and navigates us through automated phone systems. By understanding the unique history and technical reality of each, we can communicate more effectively across borders and avoid the pitfalls of this linguistic double-identity.

Frequently Asked Questions

Why is the # symbol called a pound sign in the US?

It originated from the abbreviation for "pound weight" (lb). When written quickly, "lb" with a horizontal strike-through evolved into the # symbol. Over time, it became a standard shorthand for weight in American commerce and was later adopted as the name for the symbol on telephone keypads.

Is it a hash or a hashtag?

The symbol itself (#) is a "hash" or "number sign." A "hashtag" is the combination of the hash symbol followed by a keyword (e.g., #learning). Referring to the symbol alone as a "hashtag" is technically incorrect but has become common in popular culture.

Why do some pound signs have two bars?

The two-bar style (₤) is an older typographic variant of the British pound sign. While some fonts still use it, the single-bar version (£) is the current standard for the British pound sterling. The two-bar version was also the official symbol for the Italian Lira before Italy adopted the Euro.

What is an Octothorpe?

"Octothorpe" is the official technical name for the # symbol, coined by Bell Labs engineers in the 1960s. Despite its precision, the term remains obscure to most people outside of telecommunications and typography circles.

How do I use the pound sign in a URL?

In a URL, the # symbol is used as a "fragment identifier." it points to a specific section of a webpage (e.g., example.com/page#section1). Because it has a special function, it must be URL-encoded as %23 if you want it to appear as literal text in a query string.