Light Light Lichen

Lichen

A lichen is a hybrid colony of algae or cyanobacteria living symbiotically among filaments of multiple fungus species, along with bacteria embedded in the cortex, or "skin", in a mutualistic relationship. Lichens are the lifeform that first brought the term symbiosis into biological context.

Light

Light, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometers (nm), corresponding to frequencies of 750–420 terahertz. The visible band sits adjacent to the infrared and the ultraviolet, called collectively optical radiation.

light

Noun

1. Electromagnetic radiation in the wavelength range visible to the human eye (about 400–750 nanometers): visible light.
2. Electromagnetic radiation in the wavelength range visible to the human eye or in nearby ranges (infrared or ultraviolet radiation).

Verb

1. To start (a fire).
2. To set fire to; to set burning.

lichen

Noun

1. Any of many symbiotic organisms, being associations of algae and fungi, often found as white or yellow-to-blue–green patches on rocks, old walls, etc.
2. Something which gradually spreads across something else, causing damage.

Verb

1. To cover with lichen.