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

Keep scrolling for more

Other Words from lichen

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

Examples of lichen in a Sentence

Recent Examples on the Web Cross handed me a blotter dipped in oakmoss absolute, extracted from a ghostly frisée-looking frond that is actually a lichen that grows on oak trees. Noy Thrupkaew, Washington Post, "A Big Stink in the World of Perfume," 21 Apr. 2021 This lichen from Florida was just identified from historical collections through DNA barcoding. John R. Platt, Scientific American, "What We've Lost: The Species Declared Extinct in 2020," 13 Jan. 2021 The slow-growing lichen and mushrooms upon which the reindeer depend for their survival are not found in pine or spruce plantations, so the death of one means the death of the other, and an uncertain future for an entire people. New York Times, "Wintry Scenes From a Swedish Wonderland," 21 Dec. 2020 The four-day Wukalina Walk is a thoroughly upmarket trek along Tasmania’s lichen-red Bay of Fires, where guests can gain invaluable insight into local lore and traditions. Brandon Presser, Harper's BAZAAR, "The 20 Best Places to Travel in 2021," 30 Dec. 2020 Much of the ridge was made up of basketball-sized rock, covered in black lichen that is common in sheep country. Tyler Freel, Outdoor Life, "The Dall Sheep That Almost Killed Me," 9 Sep. 2020 There, ox-eye daisies flourish from portentous box tombs, and the stone is softened by gold lichen; once-grieving cherubs wink from garlands of ivy, and extravagant calligraphy is worn to flourishes and flowers. 1843, "Can words do the dead justice?," 21 May 2020 Canada has among the highest lichen biomass in the world, competing only with Russia. Sara Miller Llana, The Christian Science Monitor, "Heads up, maple leaf. Canada’s eyeing another national icon.," 31 Mar. 2020 The relationship in the NASA myco-architectural model resembles naturally occurring lichen, which are composite organisms made of cyanobacteria and different kinds of fungi. Caroline Delbert, Popular Mechanics, "We're All Going to Live in Mushroom Houses on Mars," 16 Jan. 2020

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.

See More

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

Keep scrolling for more

Learn More about lichen

Time Traveler for lichen

Time Traveler

The first known use of lichen was circa 1657

See more words from the same year

Statistics for lichen

Last Updated

4 May 2021

Cite this Entry

“Lichen.” Dictionary, Merriam-Webster, Accessed 7 May. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Keep scrolling for more

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)

More from Merriam-Webster on 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).


Test Your Vocabulary

Star Wars Words Quiz

  • cu jedi training
  • The bounty portion of bounty hunters (such as Boba Fett) comes from a Latin word meaning
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!