Definition of Lichen

1. Noun. Any of several eruptive skin diseases characterized by hard thick lesions grouped together and resembling lichens growing on rocks.

2. Noun. Any thallophytic plant of the division Lichenes; occur as crusty patches or bushy growths on tree trunks or rocks or bare ground etc..

Definition of Lichen

1. n. One of a class of cellular, flowerless plants, (technically called Lichenes), having no distinction of leaf and stem, usually of scaly, expanded, frond-like forms, but sometimes erect or pendulous and variously branched. They derive their nourishment from the air, and generate by means of spores. The species are very widely distributed, and form irregular spots or patches, usually of a greenish or yellowish color, upon rocks, trees, and various bodies, to which they adhere with great tenacity. They are often improperly called rock moss or tree moss.

Definition of Lichen

1. Noun. Any of many symbiotic organisms, being associations of fungi and algae; often found as white or yellow patches on old walls, etc. ¹

¹ Source:

Definition of Lichen

1. to cover with lichens (flowerless plants) [v -ED, -ING, -S]

Medical Definition of Lichen

1. A large group of symbiotic associations between fungi and green and occasionally blue green algae. Several genera of algae and of fungi are involved and the associations are so stable and of such varied but distinct types that the lichens have been classified into genera and species. A variety of incompatibility phenomena are often manifest between individual lichens. Confined to terrestrial habitats and often used as indicators of pollution status of the environment. This entry appears with permission from the Dictionary of Cell and Molecular Biology (11 Mar 2008)

Lexicographical Neighbors of Lichen

lichen (current term)
lichen agrius
lichen albus
lichen amyloidosis
lichen annularis
lichen haemorrhagicus
lichen infantum
lichen iris
lichen lichens on bark
lichen myxoedematosus
lichen nuchae
lichen obtusus
lichen planopilaris

Literary usage of Lichen

Below you will find example usage of this term as found in modern and/or classical literature:

1. The American Journal of the Medical Sciences by Southern Society for Clinical Investigation (U.S.) (1886)
"36, 1885) the fact that lichen planus is met with on the glana penis, ... The white points which can be picked out of lichen patches are due to a local ..."

2. Report of the Annual Meeting (1868)
"Evidence is unanimous that lichen-growth should never occur in forests or nurseries which are the subject of proper care ; where the conditions of healthy ..."

3. The British Journal of Dermatology by British Association of Dermatology (1908)
"He was shown at the Dermatological Society of Great Britain and Ireland, and the diagnosis of " lichen annularis " suggested. , Microscopically the section ..."

4. Diseases of the Skin by Richard Lightburn Sutton (1919)
"... experimental production of the disease by the injection of tuberculin." The following are the more important members of this group : lichen ..."

5. English Botany; Or, Coloured Figures of British Plants, with Their Essential by James Edward Smith, James Sowerby (1807)
"Dillenius knew it well, and has justly arranged it near our lichen ... In writing our account of the latter we were not aware of the lichen now before us ..."

6. Experimental Researches Concerning the Philosophy of Permanent Colours: And by Edward Bancroft (1814)
"Linnaeus says, (in his Flora Lapponica) that an immense quantity of this lichen grows on the island of Aland, in the Baltic. ..."

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