No, collaboration isn’t part of it. Open Source is merely about whether you can build on and fix yourself. Collaboration implies something about the politics of how a project is run, and although openness and transparency are pleasant to run into, they’re not necessary or sufficient. For instance, suppose someone publishes a project which is licensed under an official O.S., but it’s so great that no one ever wants to contribute patches to it. That lack of contribution means it’s not collaborative — but make it less Open Source. Or a project, perhaps security-sensitive, which wants to vet contributors and control when source updates are published.
Open Source is about how you can use it, not about whether you can pad your CV with github commits.