Light from the sun; also called sunshine. The majority of the energy from the sun is divided into three parts: ultraviolet radiation, wavelengths less than about 0.4 μm; visible radiation, wavelengths between about 0.4 and 0.7 μm; infrared radiation, wavelengths greater than about 0.7 μm. There are conflicting conventions as to whether all three regions are referred to as light, or whether that term should only be applied to the visible portion of the spectrum. The ultraviolet radiation is sometimes called short waves and the infrared region, long waves.
Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon. This is usually during the hours known as day.