Other forms: foreshortened; foreshortening; foreshortens
When an artist foreshortens, she makes an object appear closer or a distance shorter than it is, to create a sense of depth in a painting or drawing.
To foreshorten is to create a kind of optical illusion simply by making lines shorter or angling the perspective in a certain way. It's a technique used in art and design, but it's also a phenomenon you may observe in the world: "The angle from which she's looking foreshortens the mountain, making it look closer." This word dates from about 1600.