A few months ago, MongoDB introduced a new license called SSPL following some conflicts with AWS. Later they presented this license to the Open Source Initiative (OSI) for approval for it to be called an 'open source' license. But as this license does not meet the open source definition given by the OSI, they simply rejected it. Now the question is: can MongoDB (or someone else) just 'call' SSPL an 'open source license'? Or is it a trademark owned by OSI? Will they get sued for just calling it that way?

(Note: I am aware of this newly coined term so called 'Source Available', and my question is not on this, but on being called "Open Source")

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    This might win the 'most ironic question' award, although judging from the answers, it is a real issue .... Jun 3, 2019 at 19:24
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    @JosephDoggie not sure if that's what you mean, but – open-source and trademark are by no means contradictory. With open source it is just as important to now what you get than with any proprietary product; that's all that trademarking is about. Jun 3, 2019 at 21:29
  • It's just that 'open source' to me means, well, 'open', but I understand your point..... Jun 4, 2019 at 12:24
  • Happy New Year, Zeeshan. Do you want to consider accepting an answer to this question, and perhaps some of your others?
    – MadHatter
    Jan 2, 2020 at 9:39
  • @MadHattersupportsMonica sure why not, thanks Jan 2, 2020 at 11:51

2 Answers 2


International trademarks can be searched online in the WIPO Global Brand Database.

  • “open source” is trademarked in some areas, none relevant for software
  • OSI holds a US trademark for “Open Source Initiative Approved License”, but no trademark for “open source” by itself

So from a legal perspective, anyone could use this term.

But from an open source software community perspective, the OSI is the arbiter of what counts as open source. They are the steward of the Open Source Definition, just as the FSF is the steward of the Free Software Definition. Technically, the term “open source” was not coined by the OSI. But OSI was immediately founded to promote that term, so for all practical purposes this is the OSI's term.

As a community consideration, calling something “open source” against the decisions of the OSI would look bad and pointless. It would demonstrate ill will towards precisely that community which is interested in (real) open source or free software.

“Unfortunately”, the open source movement has become so popular that it's also a nice brand, and some actors do seem to try to usurp this brand for their purposes. This has had mixed success. In response, OSI has run a campaign to reaffirm that the OSI's Open Source Definition defines open source.

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    Comments aren't for arguing over who to blame for our current terminology. Please don't use them for that purpose.
    – ArtOfCode
    Jun 4, 2019 at 15:17

The OSI failed to secure a trademark on "open source" in 1999, and the term remains not trademarked.

You may use "open source" to mean virtually anything you want, without legal ramifications, but to use it in a way that contravenes the OSI's definition may put you at significant social disadvantage with anyone who enjoys the culturally consistent understanding of "open source" to mean "in compliance with the OSI's definition." For a major player like MongoDB to do so would be tantamount to all-out culture warfare, which might not be to their advantage (or to the advantage of many, many other players in the FLOSS community).

Note that "source available" is not a new term, but has long been used by the OSI and others to indicate the public availability of source code, versus use of a license in compliance with the OSI's definition.

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    An anecdote: once in the mid-90's I was suffering through a vendor presentation for some ill-conceived conglomeration of collaboration software that attempted to mash email, messaging, document sharing and some other bits, in what we'd now call "groupware". They gushed on about how it was so original in concept they had to come up with a whole new name for the category it defined..."we call it 'shareware'". Which term, I can assure the younger among us, was very, very well-established by that time. So, never underestimate the blinkered, walled-garden narrow perspective of some vendors.
    – CCTO
    Jun 3, 2019 at 14:09
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    slightly related (NASA); What does it mean when a software is called open-source for US-release only?
    – uhoh
    Jun 4, 2019 at 11:45

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