Here are some good illustrations of short and broad portrait lighting.
Short lighting. Here, most of Tyler’s face is in shadow – the “shorter” portion of his face gets the key light. Short light improves dimensionality, thinning the subject.
Conversely, broad light refers to a key light covering the broader portion of face. Note that although the quality of light is nice and Tyler’s expression is comparable to the image above, he looks a little chunkier and this picture lacks some of the punch and immediacy of the one above.