It's common for terms to have a more specific meaning when combined with other terms. "Open source" has had a specific meaning now for decades, which goes beyond "you can see the source" to, among other things, "you're allowed to it without restriction".

So Swedish meatballs are any ball of meat made in Sweden?

And French fries are anything that was fried in France?

Tell that to Sam Altman

He did not succeed, did he?