As background, know that I value art above all else. The first thing I would do with millions of dollars would be to give it to people I know who are talented artists so they could focus on doing their work.
To me, art is man-made beauty. Simply put. It can take myriad forms.
One person told me she doesn't like art and I have been thinking about this on and off since then because I can't fathom how anyone could not like art! Thankfully, another friend of mine who does like art was telling me how he likes it not so much for its beauty but inasmuch as it reflects history and when he looks at it he likes to think about the context in which it was created. That made me realize that there are different ways to enjoy art.
The first person is someone who I consider an artist. She has a way with landscaping, which I consider some of the most complex and difficult art. She just sees it as enjoying nature as opposed to creating art.
To me, art is any expression in which someone manipulates the world to create beauty or to express an emotion. It can be planting flowers. It can be sculpting trash. It can be writing, singing... I have a broad definition of art. And kind of like defining life, you know it when you see it.