As an editor of a technical publication I receive many submissions that contain acronyms. A common error I witness in many people’s writing is when expanding the words of an acronym, the expanded words get capitalised.
First of all we must remember that in English, capitalisation is reserved for proper nouns. When we take a series of words and make an acronym from the first letter of each word, we usually capitalise each letter, so that the resulting new word is clearly an acronym (or initialism, which I will explain later). But this doesn’t mean that words that made up the acronym suddenly gain the status of proper nouns, unless they were proper nouns to begin with. Making an acronym does not change the status of the original series of words it represents. For example:
|Original Text/Expanded Form||Acronym/Initialism|
|World Health Organization||WHO|
Notice that the original words of PC are not proper nouns, so they are not capitalised when PC is expanded, while WHO represents (in this case) a series of proper nouns, because it is the name of an organisation.
This example is very simple. In reality, there are many ways that acronyms are made: sometimes they use more than one letter from some words (e.g. AOL stands for America Online), and sometimes they contain other acronyms (e.g. AIM for AOL Instant Messenger, where AOL stands for America Online). Sometimes they leave some of the original words out.
Abbreviations, initialisms and acronyms
First of all, we should define an acronym as a particular form of abbreviation. There are many abbreviations that are not acronyms, such as Rd for road, or Dr for doctor.
Many dictionaries express a distinction between acronyms and initialisms. They define an acronym as an abbreviation, taken from letters from each word in a series, which can be pronounced as a word (e.g. NATO), while an initialism is one which is not pronounced as a word, and is pronounced as the letters (e.g. FBI). This is really only because an initialism just happens to have a pattern of letters that is not pronounceable – it has no relevance orthographically (in written form). There are also some that get pronounced both ways, such as FAQ, or those that are pronounced as a combination of letters and words, such as CD-ROM. From a writing perspective, acronyms and initialisms are the same thing.
Words derived from acronyms
In the field of linguistics, acronyms are seen as a method of word formation and blending. That is, acronyms often take part in the evolution of new words. Over time, as an acronym becomes commonly used in everyday speech, it becomes a common word. Often this results in the acronym losing its capitalisation and becoming a word in its own right.
A good example of this is the word laser, which originally came form an acronym for light amplification by simulated emission of radiation. Obviously this would not normally happen for initialisms, because they cannot be pronounced as words.
I am not going to go into all the variations on acronyms, such as backronyms, pseudo-acronyms, or recursive acronyms. Just remember:
If an acronym came from words that are common nouns, then when expanded, the individual words are not capitalised.