Butterfly or Glamour Lighting:

The term, "Butterfly Lighting," comes from a characteristic butterfly shaped shadow beneath the subject's nose. If you want to use butterfly lighting you should line your Main Light up along your subject's nose axis and then raise the light until you see the characteristic shadow. This style of lighting is also known as glamour lighting because it was used extensively by the great Hollywood portrait photographers of the '20s, '30s and '40s. Although light placement is identical for butterfly and glamour lighting, photographers such as George Hurrell gave it a special look by using a spotlight as the Main Light rather than a softer light source.