Nat Torkington asked recently Is "Open Source" Now Completely Meaningless. Certainly not; in fact, there are several reasons this label is still valid and important. I'm a pragmatist, so I'm not going to wave any flags or sing any anthems to argue this, just point out what has worked and continues to work.
First of all, let's be clear about what "open source" means. Software is 'open source' when it is issued under a license compliant with the Open Source Definition. Nothing any clueless or malevolant corporate marketeer does can change that, because the term originated in the open-source developer community and only we have the authority to redefine it.