noun

lichen

LEYE-kuhn

Lichen (noun) means a slow-growing organism formed by algae and fungi living together, often seen as pale or greenish patches on rocks, trees, or walls. Example: “Thick lichen covered the old stone wall.”

noun

A slow-growing organism formed by algae and fungi living together, often seen as pale or greenish patches on rocks, trees, or walls.

"Thick lichen covered the old stone wall."

"Scientists study lichen because it's sensitive to air pollution."

How to use lichen

Learner’s notes

In plain EnglishA crusty or leafy organism, part fungus and part alga, that grows on rocks, bark, and similar surfaces.

Common pairings

lichen-covered a patch of lichen

Word forms

lichened past tense, lichens plural, lichen plural, lichens singular

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Fill the gap

Can you complete this real example?

Thick _____ covered the old stone wall.

Etymology

From Latin lichen, from Ancient Greek leikhḗn, related to leíkhō, "to lick" — the name likely comes from how the growths seem to "lick" or spread across a surface.

Origin: Ancient Greek

Frequently asked questions

What does “lichen” mean?

The word “lichen” means a slow-growing organism formed by algae and fungi living together, often seen as pale or greenish patches on rocks, trees, or walls. In plain terms, a crusty or leafy organism, part fungus and part alga, that grows on rocks, bark, and similar surfaces.

How do you pronounce “lichen”?

“Lichen” is pronounced LEYE-kuhn (/ˈlaɪ.kən/ in IPA).

How do you use “lichen” in a sentence?

Here is “lichen” used in a sentence: “Thick lichen covered the old stone wall.”

What part of speech is “lichen”?

“Lichen” is a noun.

Where does the word “lichen” come from?

The word “lichen” comes from Ancient Greek. From Latin lichen, from Ancient Greek leikhḗn, related to leíkhō, "to lick" — the name likely comes from how the growths seem to "lick" or spread across a surface.