I recently had the occasion to try and find a definition of “proprietary” in terms of software that is not on Wikipedia. Most of the discussion on the issue I found was focused on what free and open source software is, and that anything that isn’t FOSS is proprietary. I don’t think the debate is as simple as this, especially if you want to get into conversations about nuance around things like Open Core.
The problem with defining proprietary software by what it isn’t, or at least that it isn’t FOSS, means that we cannot concisely communicate what makes something proprietary. Instead, we leave it up to the people we’re trying to communicate with to dig through a history of rhetoric, copyright law, and licensing in order to understand what it actually means for something to be FOSS, and what it means for something to be anything else. It is also just less satisfying, in my opinion, to define something by what it lacks rather than by what it is.
I’ll start by proposing the following definition:
Proprietary software is software that comes with restrictions on what users can do with the software and the source code that constitutes said software.
I think the most controversial part of this sentence is the wording “software that comes with restrictions.” In earlier attempts of this I wrote “software that restricts.” This sort of active wording, which I used for years in my capacity at work, is misleading. In the case of proprietary software, it is the licensing and laws around it that restrict what you can do. For software to restrict you, it must be that the way the software is being implemented or used restricts you.
To be clear, this is my first proposal. I look forward to discussing this further!