I'm translating for a company that creates specialized 3D software. In a lot of the brochures, there are bullet points for things like '3D road design.' or '3D visibility.' To my eye, the words 'road' and 'visibility' should be capitalized in these contexts.

To be clear, I'm asking about the cases in which 3D begins a sentence, and whether I should capitalize the word that comes after it.

Am I right? Is this basically on a how-you-like-it basis?

Additional question (really just curiosity): when I search for questions like this, is 3D an abbreviation or an acronym? I feel like it would technically be an abbreviation of an acronym?

  • I have always learned that the first complete word in a sentence should be capitalized, which would mean that you are right. However, the people that told me that were not talking about English, so I wonder if there is a similar rule in English indeed. :)
    – oerkelens
    Commented Apr 28, 2014 at 8:04
  • Type the four characters 3-D# (where # is my attempt to show a space) into Google, then select any entry from the drop-down menu you get. Ignore all the obvious titles / proper names / 'happy-cappy' strings ('3-D Is Your Best Buy'). Look only at sentences beginning with 3D, 3-D, 3d etc. You will see that some sentences are rendered eg '3D printing or additive manufacturing ...' , '3D tattoo art ...' while others do capitalise the next word after 3-D. Commented Apr 28, 2014 at 8:22
  • @EdwinAshworth: It looks then like the rule is to not capitalize the word folling 3D (using your method I didn't find any examples where it was capitalized). Random etiquette question: is it considered good form now to answer my own question with what I've found? Commented Apr 28, 2014 at 8:34
  • 2
    If you want a bit of support for the practice, Wiki answers has the related 'If you start a sentence with a number do you put a capital letter on the first word?' _'No you don't; if the sentence starts with a number then that number counts as the first word for the purpose of capitalization rules. Example: 1990 was a good ...' Although I've also seen dictators write 'Never begin a sentence with a numeral'. Commented Apr 28, 2014 at 9:13
  • Shouldn't it be "Three dimensional" instead of 3D, since the rule is to never start a sentence with a number?
    – user196513
    Commented Sep 15, 2016 at 23:24

1 Answer 1


Consider the following two sentences:

3D visibility is needed for best response times.

3D Visibility is needed for best response times.

In my opinion, the 1st statement is talking generally about visibility in 3D, whereas the 2nd statement seems to refer to a product (e.g. software?) called 3D Visibility.

I agree with Edwin that the rule for capitalising a sentence is that only the first word needs to be capitalised; but since numeric digits have no uppercase version, no capitalisation is required.

  • I've reached a place where I agree wholeheartedly. I guess I just have to retrain my eyes to like the 'look' of the first one more. Commented Apr 29, 2014 at 11:53

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