Illumination or lighting is the deliberate use of light to achieve a practical or aesthetic effect.

Illumination might be provided through the use of artificial light sources like lamps and light fixtures, or natural illumination by capturing daylight.

Daylighting (using windows, skylights, or light shelves) is sometimes used as the main source of light during daytime in buildings.

Specialised forms of artificial lighting have been developed to suit every possible situation and purpose where natural light is not available.