If you want to study painting, go to art school. If that doesn’t work out, maybe you can get a job painting houses. Then you can paint a house purple or paint a picture, which is called a painting.
Slapping a coat of paint on your apartment walls is painting, but so is creating a masterpiece like Van Gogh's "Starry Night" or maybe even C.M. Coolidge’s “Dogs Playing Poker.” The picture that results from your painting experiments is also called a painting. The Latin root of painting, pingere, means "to paint," but also "to stain, embroider, or tattoo."