The UK Rules
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Rules for Acronyms

Learn how to punctuate acronyms and capitalize familiar initialisms which are used in writing for abbreviation and clarity, as a rule.

ACRONYM RULES OF USE: You should use acronyms and other shortened phrases cautiously and correctly when you write to communicate because misuse of an acronym or initialism is more likely to confuse than clarify.

How and When to Use Acronyms

The Correct Usage of Acronyms and Initialisms provides writers with an opportunity to make your writing clearer for the reader.

But take note that misusing them may turn your memos and letters into a confusing mess and accomplish nothing more than a page of argle-bargle.

Using these writing tips below will help all authors and communicators use acronyms and slang initialisms correctly in business and in letter writing.

You can bookmark this guide so you know when you can - and when you definitely should not - use word abbreviations and acronyms.

What is an Acronym?

A contemporary acronym is an abbreviated word formed by using the initial component letters of another name, word, or phrase. Acronyms are pronounced as if they are a word themselves, as a rule.

Shortened word components can be used as individual letters such as in UNICEF (United Nations International Children’s Emergency Fund) or used in pieces of words or names such as in Benelux (Belgium, The Netherlands, and Luxembourg).

The Longest Acronym

The Correct Usage of Acronyms and InitialismsIn English, the longest acronym in present day use is a navy term - 'Adcomsubordcomphibspac'.

The exorbitant and lengthy 'abbreviated' acronym (which perhaps needs further abbreviation) stands for Administrative Command, Amphibious Forces, and Pacific Fleet Subordinate Command.

Can you imagine having to write that phrase multiple times in a 100-page document for your commanding officer?

Three-letter Acronyms (TLA)

A three-letter acronym (TLA) or three-letter abbreviation is a term (acronym, alphabetism, or initialism) which consists of three letters.

As a rule they are the initial letters of the abbreviated words or phrase and should be written in capital letters (upper case).

Most three-letter abbreviations are actually initialisms which means all the letters are pronounced as the names of letters.

There are also some three letter acronyms pronounced as a word such as in the phrase 'CAT' scan, meaning computed axial tomography. 'TLA' is in fact a TLA and an example of a self-referencing definition, however, etc. and Mrs. are not three-letter acronyms.

Longest TLA (pronounced)

The longest three letter acronym 'TLA' possible to pronounce in English is 'WWW' requiring the use of nine syllables when it is spoken correctly.

The usefulness of three letter acronyms comes from how much quicker it is to speak the abbreviation than the phrase which they represent.

Nonetheless, pronouncing 'WWW' in English requires the speaker to use three times as many syllables than the phrase itself - World Wide Web.

Because of this strange anomaly, 'www' is often abbreviated in speech to 'dubdubdub'.

What is an Initialism?

Initialisms (in a nutshell) are shorter forms of words or phrases. The general rules for using initialisms can come in especially handy when you need to repeat the same word or phrase many times throughout the same piece of writing.

You should pronounce an initialism as a series of letters.

An example would be 'NATO' which stands for North Atlantic Treaty Organization. Writing initialisms in communication can save you a lot of time and keep your business documents from sounding repetitive and lengthy.

10 Rules for Acronyms and Initialisms

  1. Acronyms should only be used for words or phrases that are repeated a number of times throughout your document
  2. Write acronyms in uppercase capital letters (as a rule) LOL
  3. To reduce confusion for the reader and to retain their interest, avoid using unfamiliar acronyms in general and especially not in your introductory paragraph
  4. Check to see if an established initialism or acronym already exists for your phrase before you make one up (use casual initialisms only in text messages)
  5. You can use a combination of upper and lower case letters if the acronym contains at least four letters and is pronounceable (Nasa)
  6. Full stop (periods) are not required in contemporary acronyms (Scuba)
  7. As a general rule of thumb, write out the full name when it is initially written and then follow that by writing the acronym in brackets (parenthesis) and repeat the bracket form if it is used again later in the same passage
  8. There is no need to write an explanation of most familiar or popular acronyms because we can assume readers will recognize them
  9. Use the sound of the acronym to determine which article precedes the vowel ('an' in place of 'a' such as in 'a Unicef’ issue') because nouns require articles written before them
  10. It is rarely necessary to use the word 'the' before most acronyms when they are pronounced as words (Interpol)

And Finally... TTFN

TTFN is an initialism which represents the colloquial valediction, 'ta ta for now'. The friendly expression is used as an informal 'goodbye' or 'goodbye for now' but it actually came to prominence during the Second World War in the United Kingdom.

Acronym Rules in Writing; Updated 2017