Reply to The Concept of a Remix

A long time ago in a studio far far away, I was told that a remix is supposed to be a complete and total 2nd take on a song that uses the same instruments. Some where else i was told that all a remix requires is a new set of lyrics. "But what if the song doesn't have lyrics?" Then it has to use different instruments i was told.

Right now at this very moment my facebook feed is being flooded with "remixes", but none of them are like either of the above. They are all minimally changed and easily mistakable for the original song if you ask me. SO by that logic they are not remixes. But when i confront the "remixer" they claim the song is a remix.

All of this has led me to wonder:

What truly defines a remix? What has to be changed or added to consider it a remix? And what is the absolute least you can do to a song to consider it a remix? If you remix a remix is that considered a VIP or is that only when you remix your own recording?

Thanks for your help, it shall be greatly appreciated.