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 Such an ancient community likely would have been tuned for an oxygen-deficient environment and devoid of lichens, which are thought to have evolved only in the last 250 million years. Zack Savitsky, Quanta Magazine, 12 July 2023 The blue is grayish yet luminous in Saylor’s delicate illustration of moonglow lichen scattered across a field of textured brown. Mark Jenkins, Washington Post, 2 Feb. 2024 Irena’s novel about lichen is said to have led to the enactment of EU-wide environmental protection legislation—as well as threats of rape, death, and deportation, and nominations for every extant literary award. Nathan Jeffers, Hazlitt, 28 Feb. 2024 In addition to Belgica antarctica, the terrestrial ecosystem is composed of just a handful of small animals like springtails (a type of tiny arthropod), a smattering of microorganisms and low-lying ground cover such as lichen. Popular Science, 15 Feb. 2024 With scarce food in this habitat, the mouse likely only has lichens and the occasional insect to eat. Jack Knudson, Discover Magazine, 6 Feb. 2024 This lichen seems to be unique to the warmer and drier forests in California’s Sonoma and Santa Cruz counties, in the southern part of coast redwoods’ range. Discover Magazine, 6 Jan. 2024 Reindeer subsist largely on light-colored reindeer moss, which isn’t actually a moss but rather a type of lichen that grows in crunchy, carpet-like patches across northern latitudes. Holly Ramer, Fortune, 24 Dec. 2023 In the winter, the lichens absorb ultraviolet light, while the snow reflects it. Gabe Allen, Discover Magazine, 12 Dec. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'lichen.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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 20 Apr. 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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