People are capable of near infinite concepts and ideas. Writing, painting, singing, talking, movies and many more are all means by witch you can convey your ideas to another. But did they get it? How clearly do your words get across a 3D object? If you drew a picture of a celebrity would people that see it recognize the celeb?
Art is simply how well you can use the tools and techniques of any medium to get that medium to communicate a thought, person, action, feeling, you name it.
"In the movie, you see the battle field and right away you know this is going to be epic. The music starts slowly and your heart starts pounding. You see the ferocity on faces and feel the desperation these people had. The weapons shatter under steel and muscle. It was only then that I realized what it must have been like and what these people had to go through to win their freedom." Now that is art.
Also: That produced by an "artist". It comes in many forms:painting, pencil-drawing, sculpture, etc. The medium isn't important as long as the creation is unfathomable to all but the exceedingly rich and outstandingly gay, who only pretend to understand it anyway and write protracted essays on it aimed at the terminally dull. Amongst those 2 classes of people a piece of art will often engender much chin-rubbing in bizarrely-lit art galleries. The practitioners of art are invariably pretentious individuals who consider themselves superior to all other people. In fact some artists take up the occupation in order to further remove themselves from normal, right-thinking people.