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
Armed with precise instructions, children collected 8,000 samples of mosses and lichens from local parks, forests and other spots.
—
Paulina Rowińska, Smithsonian Magazine, 12 Mar. 2025
Some 20 films from 17 countries, all of them focusing on and/or dedicated to the beauty of lichens, micro fungi and mushrooms, will be screened over two-plus hours.
—David L. Coddon, San Diego Union-Tribune, 3 Apr. 2025
The abstract artwork celebrates the island's natural diversity by referencing local flora such as lichen, prickly pear, and agave leaves.
—Skye Sherman, Travel + Leisure, 23 Feb. 2025
Old-growth trees exhibit more extensive and complex root structures that are host to a diverse ecosystem of mosses, lichens and animals.
—Stephen Underwood, Hartford Courant, 4 Mar. 2025
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Paulina Rowińska, Smithsonian Magazine, 12 Mar. 2025
Some 20 films from 17 countries, all of them focusing on and/or dedicated to the beauty of lichens, micro fungi and mushrooms, will be screened over two-plus hours.
—David L. Coddon, San Diego Union-Tribune, 3 Apr. 2025
The abstract artwork celebrates the island's natural diversity by referencing local flora such as lichen, prickly pear, and agave leaves.
—Skye Sherman, Travel + Leisure, 23 Feb. 2025
Old-growth trees exhibit more extensive and complex root structures that are host to a diverse ecosystem of mosses, lichens and animals.
—Stephen Underwood, Hartford Courant, 4 Mar. 2025
See All Example Sentences for lichen
Cite this Entry
“Lichen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lichen. Accessed 22 Apr. 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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