Illustration of lichen
- lichen 1
1
: any of numerous complex plantlike organisms made up of an alga or a cyanobacterium and a fungus growing in symbiotic association on a solid surface (such as on a rock or the bark of trees)
Note: The main body of the lichen, known as the thallus, is formed by fungal filaments which surround the photosynthetic algal or cyanobacterial cells. The lichen is usually described as having a leaflike (foliose), crusty (crustose), or branching shrub-like (fruticose) form. Lichens often play an important part in the weathering of rocks and include some that are sources of natural dyes.
2
: any of several skin diseases characterized by the eruptions of flat papules
Examples of lichen in a Sentence
Recent Examples on the Web
Those are lichens growing on the surface of the grapefruit bark.
—
Tom MacCubbin, Orlando Sentinel, 18 Jan. 2025
The scientists discussed pioneer species — like moss, mold and lichens — which could be introduced to Mars and set the stage for terraforming the planet.
—Tom Brown, Space.com, 9 Jan. 2025
Plants moved in: an ecological succession of lichens, mosses, grasses, shrubs, and deciduous trees.
—Kevin West, Travel + Leisure, 4 Jan. 2025
California has a state lichen, while Alabama has a state Bible.
—Casey Cep, The New Yorker, 28 Dec. 2024
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Tom MacCubbin, Orlando Sentinel, 18 Jan. 2025
The scientists discussed pioneer species — like moss, mold and lichens — which could be introduced to Mars and set the stage for terraforming the planet.
—Tom Brown, Space.com, 9 Jan. 2025
Plants moved in: an ecological succession of lichens, mosses, grasses, shrubs, and deciduous trees.
—Kevin West, Travel + Leisure, 4 Jan. 2025
California has a state lichen, while Alabama has a state Bible.
—Casey Cep, The New Yorker, 28 Dec. 2024
See all Example Sentences for lichen
Dictionary Entries Near lichen
Cite this Entry
“Lichen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lichen. Accessed 8 Feb. 2025.
Copy CitationKids Definition
lichen
noun
li·chen
ˈlī-kən 
: any of numerous plantlike living things made up of an alga and a fungus growing together on a solid surface (as a rock or a tree)
Medical Definition
lichen
noun
li·chen
ˈlī-kən
1
: any of several skin diseases characterized by the eruption of flat papules
especially
: lichen planus
2
: any of numerous complex plantlike organisms made up of an alga and a fungus growing in symbiotic association on a solid surface (as a rock)
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