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.
Best Answer
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.
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).