I'm wondering when to use or not to use the definite article, when using acronyms or initialisms in a sentence. Is there a rule for this, or does it depend on the context?

For example, let's look at some example sentences
DDR = detailed design review.

NASA is planning to launch the final shuttle soon (no article)
The FBI shut down this website (article)
ESA is a full partner in the ISS (no article, article)
The project was cancelled at the DDR. (article)

What confuses me is that if NASA or ESA would be written in full, the article would be necessary.


Generally the article is not used with acronyms (initials that can be pronounced as a word), whereas it is with initialisms (initials where the letters themselves are pronounced). I would actually use the article with 'ESA' in the examples you gave, and so 'NASA' (acronym) doesn't get an article, but 'FBI', 'ESA', and 'DDR' (initialisms) do.

That said, there are initialisms where one wouldn't use the article either; you can usually work it out by expanding it and seeing whether you would use the article with the full sentence. Is the initialism talking about a specific thing (use the article), or a notion in general (don't use the article)? eg.

  • The CPU is overheating (The Central Processing Unit is overheating).
  • DRM is bad for consumers (Digital Rights Management is bad for consumers).

Acronyms don't tend to ever get an article, however (at least I can't think of any) because once they become pronounced as a name, they are treated like proper nouns, which don't receive an article (James did this; Microsoft did that; France did this; NASA did that).

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    I think that ESA is used as acronym as well, so that would be compliant with your answer. However, I can think of examples where initialisms wouldn't get an article, or the reverse. For example: "CNN just released some breaking news", "The TV isn't working", "I attend UCSD (english.stackexchange.com/questions/10020/…)". How would you account for these? – JackStoneS Jun 20 '11 at 13:39
  • @jez I see you extended your answer somewhat. It makes sense to me that acronyms are treated as proper nouns. That would also explain the lack of an article for CNN, since it is used as the name of the company. Thanks for the explanation. – JackStoneS Jun 20 '11 at 14:06
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    A very elegant answer. – The Raven Jun 20 '11 at 14:37
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    UCSD is a case which doesn't match Jez's proviso (it is an initialism used as a name, which does have "the" when expanded); but I think it is an exception. – Colin Fine Jun 20 '11 at 14:59
  • There are a number of exceptions, as some usages are dictated by convention that overrides a formal rule in this case (e.g., abbreviated university names). – The Raven Jun 20 '11 at 15:45

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