It is a type of side lighting, similar to split lighting, except that the side of the face that is in shadow has a triangle of light under the eye.
This style of lighting is named after the way that Rembrandt used light in his portrait paintings. It is a type of side lighting, similar to split lighting, except that the side of the face that is in shadow has a triangle of light under the eye. This can be highly effective in making a two-dimensional image appear three dimensional.