What is the difference between direct, indirect, semidirect, and semi-indirect lighting?

In the context of interior design and architecture, lighting methods are categorized by how light is distributed from the source to the environment. These methods are defined as follows:

• Direct lighting: A method where the greater part of the light travels directly from the source to the area being illuminated.1
• Indirect lighting: A system in which light emitted by a source is diffusely reflected, typically off surfaces like the ceiling, to illuminate a space.2
• Semidirect lighting: A combination of methods where a significant portion of light is directed downward, while some is reflected off surfaces like the ceiling.3
• Semi-indirect lighting: A method using a translucent reflector that transmits some primary light downward while reflecting the majority of the light toward the ceiling.43

Designers often utilize these techniques to control lighting intensity, create highlights and shadows, and avoid the monotony of uniform illumination.35