Open is a means, not a movement
In the humble beginnings of the GNU and Linux projects, open source was a primitive and narrowly-defined idea. It applied only to programming, and was a largely legal designation that sought to guarantee that source code remained available to users even as others augmented it through subsequent contributions.
Now, thirty years later, “open” is sweeping the enterprise. On top of “open source,” we also have “open data,” “open management,” “open design,” “open organizations,”—and even just “open,” which we often take to imply something vague about a progressive policy.