li·​chen | \ ˈlī-kən How to pronounce lichen (audio) , British also ˈli-chən\

Definition of lichen

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

Illustration of lichen

Illustration of lichen

lichen 1

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Other Words from lichen

lichened \ ˈlī-​kənd How to pronounce lichened (audio) , British also  ˈli-​chənd \ adjective
lichenous \ ˈlī-​kə-​nəs How to pronounce lichenous (audio) , British also  ˈli-​chə-​ \ adjective

Examples of lichen in a Sentence

Recent Examples on the Web

The little guests were able to take turns feeding the animals handfuls of lichen. Chloe Foussianes, Town & Country, "Duchess Camilla Gets into the Christmas Spirit, Hangs Out with a Couple Reindeer," 7 Dec. 2018 The toughest Earth creature could be the water bear, or tardigrades, which are .04 inch long invertebrate animals that live in mosses, soil, or lichens on earth. Joe Pappalardo, Popular Mechanics, "What Would Life on Mars Be Like?," 25 July 2018 The blues even have a little bit of a green undertone, like lichen on a stone. Lisa Cregan, House Beautiful, "Susan Ferrier on Creating a Cozy Lake House With Dark Colors," 18 Aug. 2014 Sometimes pain during intercourse is medical in nature, such as conditions like vulvodynia and lichen sclerosus. Sarah Jio, Woman's Day, "7 Common Reasons to Seek Sex Therapy," 8 Oct. 2010 BETA GLUCANS Long-chain sugar molecules found in the cell walls of bacteria, fungi, yeasts, algae, lichens, and grains, such as oats and barley. Allure, "The Skin-Care Glossary: A Comprehensive Guide to Everything You Need to Know," 17 Aug. 2018 Their three variations, known as ecomorphs, include a brown spider that lives among rocks, a gold spider that lives under leaves, and a white spider that lives on lichen. Sophie Weiner, Popular Mechanics, "Hawaiian Spiders on Different Islands Evolved the Same Traits," 9 Mar. 2018 Most likely the gray growth is from lichens formed from a combination of harmless fungus and algae. Tom Maccubbin,, "Prune blueberry bushes after fruiting," 23 June 2018 If lichens need control, a copper-containing fungicide specific for figs or a general fruit tree use can be applied to reduce their growth following label instructions. Tom Maccubbin,, "Caterpillar invasion isn't end for healthy tree," 14 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'lichen.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of lichen

circa 1657, in the meaning defined at sense 2

History and Etymology for lichen

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

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Dictionary Entries near lichen


lich bird





lichen green

Statistics for lichen

Last Updated

23 Apr 2019

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Time Traveler for lichen

The first known use of lichen was circa 1657

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More Definitions for lichen



English Language Learners Definition of lichen

: a type of small plant that grows on rocks and walls


li·​chen | \ ˈlī-kən How to pronounce lichen (audio) \

Kids Definition of lichen

: a plantlike organism made up of an alga and a fungus growing together


li·​chen | \ ˈlī-kən How to pronounce lichen (audio) \

Medical Definition of lichen

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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More from Merriam-Webster on lichen

Rhyming Dictionary: Words that rhyme with lichen

Spanish Central: Translation of lichen

Nglish: Translation of lichen for Spanish Speakers Encyclopedia article about lichen

Comments on lichen

What made you want to look up lichen? Please tell us where you read or heard it (including the quote, if possible).


one that collects or salvages junk

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