lichen

noun

li·​chen ˈlī-kən How to pronounce lichen (audio)
 British also  ˈli-chən
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
lichened
ˈlī-kənd How to pronounce lichen (audio)
 British also  ˈli-chənd
adjective
lichenous
ˈlī-kə-nəs How to pronounce lichen (audio)
 British also  ˈli-chə-
adjective

Illustration of lichen

Illustration of lichen
  • lichen 1

Examples of lichen in a Sentence

Recent Examples on the Web
These examples are automatically compiled from online sources to illustrate current usage. Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Zayn Malik Postpones Shows, Cowell And Cole React Why Fungi Matter Fungi, including mushrooms, mold, yeast, mildew, and lichen, are critical to maintaining natural habitats. Daniela De Lorenzo, Forbes, 20 Oct. 2024 Fortunato Gatto comes across a gnarled old birch tree adorned with pale ‘old man’s beard’ lichens. Cecilia Rodriguez, Forbes, 9 Oct. 2024 Today, Mars is seen as being so inhospitable to life that anyone who found a patch of lichen on the planet would be a shoe-in for a Nobel Prize. David Szondy, New Atlas, 8 Oct. 2024 Inches, or sometimes several feet, of organic matter remain on the soil even as new trees, moss and lichen, one of the caribou’s favorite foods, grow on top. Manuela Andreoni, New York Times, 13 Aug. 2024 See all Example Sentences for lichen 

Word History

Etymology

Latin, from Greek leichēn, lichēn, from leichein to lick

First Known Use

circa 1657, in the meaning defined at sense 2

Time Traveler
The first known use of lichen was circa 1657

Dictionary Entries Near lichen

Cite this Entry

“Lichen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lichen. Accessed 13 Nov. 2024.

Kids Definition

lichen

noun
li·​chen ˈlī-kən How to pronounce lichen (audio)
: 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 How to pronounce lichen (audio)
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)

More from Merriam-Webster on lichen

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