What makes art/not art?

What makes something ART or Art or art? What is art is the first question tackled in an art history survey. I’ve been thinking about it for a long time now, and my best answer is just another question: What ISN’T art?

I once annoyed everyone (but most effectively my science major friends) by saying that really art should be called “biology,” since it is the real study of life. Hubristic statements aside, maybe we need a new term for art, something that can properly encompass all the mediums and ways and iterations of art out there.

Most recently, I’m thinking about what zines are- are they a medium, a method, a platform, ephemera? To me they’re art, but so is everything, so how to distinguish between what is an Art Object, what is Printed Ephemera, and what is just a xerox? I can see that intersectionality is the way to the best answer, as usual, but I still want my taxonomical questions addressed. Everything seems to demand iteration.

Is there anything that is definitely not art at all?