lichen
[ lahy-kuh n ]
/ ˈlaɪ kən /
noun
any complex organism of the group Lichenes, composed of a fungus in symbiotic union with an alga and having a greenish, gray, yellow, brown, or blackish thallus that grows in leaflike, crustlike, or branching forms on rocks, trees, etc.
Pathology.
any of various eruptive skin diseases.
verb (used with object)
to cover with or as if with lichens.
Origin of lichen
1595–1605; < Latin
līchēn < Greek
leichḗn
OTHER WORDS FROM lichen
li·chen·i·za·tion, noun li·chen·like, adjective un·li·chened, adjectiveWORDS THAT MAY BE CONFUSED WITH lichen
lichen likenWords nearby lichen
Example sentences from the Web for lichen
British Dictionary definitions for lichen
lichen
/ (ˈlaɪkən, ˈlɪtʃən) /
noun
an organism that is formed by the symbiotic association of a fungus and an alga or cyanobacterium and occurs as crusty patches or bushy growths on tree trunks, bare ground, etc. Lichens are now classified as a phylum of fungi (Mycophycophyta)
pathol
any of various eruptive disorders of the skin
Derived forms of lichen
lichened, adjective lichen-like, adjective lichenoid, adjective lichenous or lichenose, adjectiveWord Origin for lichen
C17: via Latin from Greek
leikhēn, from
leikhein to lick
Medical definitions for lichen
lichen
[ lī′kən ]
n.
Any of various skin diseases characterized by patchy eruptions of small, firm papules.
Scientific definitions for lichen
lichen
[ lī′kən ]
The mutualistic symbiotic association of a fungus with an alga or a cyanobacterium, or both. The fungal component of a lichen absorbs water and nutrients from the surroundings and provides a suitable environment for the alga or cyanobacterium. These live protected among the dense fungal hyphae and produce carbohydrates for the fungus by photosynthesis. Owing to this partnership, lichens can thrive in harsh environments such as mountaintops and polar regions. The more familiar lichens grow slowly as crusty patches, but lichens are found in a variety of forms, such as the tall, plantlike reindeer moss. The association between the different organisms in a lichen is so close that lichens are routinely referred to as a single organism, and scientists classify lichens using the name of the fungal component.