We have an word game commercial mobile application for which we want to use dictionaries for various languages. Most of them have GPLv3 or CC-NC3 licenses.

We modify the dictionaries: basically, we filter out some unallowed words and convert them from TXT to DAWG. The resulting files are not distributed along with the app. The app downloads a list of them, the user chooses one and uses it. The user is not able to provide his own dictionary (that is, the application downloads from fixed URL). However, if he asked us to add one, we may do so.


  1. is this usage complying with GPLv3?
  2. is this usage complying with CC-BY-NC3?

It is obvious, that a commercial app can work with GPL data. The problem probably reduces to whether our way of usage is considered "part of an application" or "linking".

  • 3
    My gut-feeling would be: GPL is ok (does not link/works technically without GPL code, one of the reasons why GPL should not be used for assets), CC-BY.NC3 no. But as a business, do you want to rely on non-lawyer-approved information from the internet?
    – kat0r
    Commented Mar 15, 2016 at 8:44
  • @kat0r With CC-BY.NC3: question is who is licensee? Is it we (authors of the commercial app) or the user, who uses our app to use the content? If we provided a way for the user to download from URL he provides, will that change? Are we required to provide such functionality by the terms of CC-BY-NC?
    – Oliv
    Commented Mar 15, 2016 at 9:18
  • You either provide the user access to the licenced file, by hosting it yourself (which would violate the licence, imho), or link to some public resource (which probably does not), which could lead to people adding dicks to your dictionary/the download not working.
    – kat0r
    Commented Mar 15, 2016 at 9:43

2 Answers 2


As your application can read any dictionary that has been converted into the right format, those dictionaries are "mere data" for your application. This means that the copyright licenses of the dictionaries don't affect the copyright of your application.

To comply with the GPL license of the dictionaries that come with that license, you must make your modified version of the library also available under the GPL license. This probably means that you must have a possibility to download the dictionary (in both DAWG and TXT format) from outside the application.

For the CC-NC license, it is less clear cut.
The term "commercial use" is not all that well defined, so the interpretation can differ widely. To be on the safe side, you should assume that "used by an application that makes money for someone" is covered by commercial use until you have received a definitive statement to the contrary from the copyright holder of the specific dictionary that you would like to use.

  • Where is the quote "used by an application that makes money for someone" from?
    – Oliv
    Commented Mar 16, 2016 at 11:51
  • For CC-NC, the dictionary is not "mere data"? What if I open that CC-NC dictionary in Microsoft Word, that also makes money for Microsoft?
    – Oliv
    Commented Mar 16, 2016 at 11:53
  • @Oliv: It is not a quote from someone. Just a phrase that I could imaging being used to mean commercial use. Commented Mar 16, 2016 at 11:53
  • @Oliv: That is one of the big problem with NC licenses: Where is the line between commercial and non-commercial use. That is why I would urge you to clarify with the copyright holders of the libraries if they would consider your use to fall under NC. Commented Mar 16, 2016 at 11:56
  • If we consider the dictionary as "mere data", the only problem I see with CC-NC is whether preparing the list of dictionaries that we endorse to users could be considered a commercial use. CC defines NC as "primarily intended for or directed toward commercial advantage or monetary compensation.". It definitely increases the attractiveness of our app, but only in the way that a highway increases the attractiveness of a car. If there are no roads, car is usable but less attractive, comparing e.g. with a horse.
    – Oliv
    Commented Mar 16, 2016 at 12:08

Disclaimer: the following answer does not constitute a legal advise. I am not a lawyer, so it's only a personal opinion.

1) I understand GPL3 to fully apply to dictionaries. Here the relevant quotes:

  • "'The Program' refers to any copyrightable work licensed under this License.": a dictionary seems to be copyrightable unless you could prove the contrary (by claiming that it's not original enough, but will your argument hold in front of a court ?).
  • "The 'source code' for a work means the preferred form of the work for making modifications to it. 'Object code' means any non-source form of a work.": here source would be TXT and the object DAWG.
  • "A “covered work” means either the unmodified Program or a work based on the Program.": It seems that the fact that you technically don't link your app with the text but just download parts of GPL protected work doesn't change very much the situation. Your app (a word game) is based on the dictionary.

2) Your intended usage seems not compliant with CC-BY-NC3: "You may not use the material for commercial purposes" should be incompatible with "We have a commercial mobile application".

As a conclusion, I would strongly advise you to search for qualified legal advise to analyze intellectual property matters for a commercial project. IP is serious and could significantly impact your business if not well anticipated.

  • Maybe it's important to note, that the app is well usable without the dictionaries. Actually, the free version is usable (not just a demo) and does not allow you to choose a dictionary. The difference is, that you cannot validate the words you create. It's scorabble.com.
    – Oliv
    Commented Mar 16, 2016 at 6:14
  • I can understand your argument, but as you can see, the interpretation of the gpl could be larger than expected. "Depend" is also an imprecise term. The fact tha you may have to update your code if the txt file format changes shows that there is some kind of dependency. The risks for a commercial product should be evaluated carefully
    – Christophe
    Commented Mar 16, 2016 at 6:32
  • Consider this: We will setup a repository, where users could upload dictionaries (in TXT format). The repository will convert to DAWG format. We will moderate the repository (i.e. reject spam). Our app will then use the repository. The uploader and the end user will be responsible for adhering to GPL and CC-NC. That is, in case of NC, not use our app with that dictionary for commercial activity. We will show the license to the end user. Our position is similar to that of youtube and CC-NC video on it.
    – Oliv
    Commented Mar 16, 2016 at 7:47
  • Holding a moderated repository doesn't make the things simpler, as you will become a service provider eventually with editorial responsibility. And we all know what happened to Megaupload, who thought they wouldn't be responsible for user uploads...
    – Christophe
    Commented Mar 16, 2016 at 8:36
  • There will be 10-20 such dictionaries. We will only allow legal uploads.
    – Oliv
    Commented Mar 16, 2016 at 9:40

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