This site provides many quick, easy-to-get-with examples of what a work of art is.
I have just discovered the best written description I’ve ever seen that communicates this — without the use of examples. It is by the great poet, Walt Whitman. Here it is:
The land and sea, the animals, fishes, and birds, the sky of heaven and the orbs, the forests, mountains, and rivers, are not small themes … but folks expect of the poet to indicate more than the beauty and dignity which always attach to dumb real objects … they expect him to indicate the path between reality and their souls.
A work of art indicates the path between reality and your soul!
Fantastic! Do you feel that?