lichen

play
noun li·chen \ˈlī-kən, British also ˈli-chən\

Definition of lichen

  1. 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) 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 shrublike (fruticose) form. Lichens often play an important part in the weathering of rocks and include some that are sources of natural dyes.

  2. 2 :  any of several skin diseases characterized by the eruptions of flat papules

lichened

play \ˈlī-kənd, British also ˈli-chənd\ adjective

lichenous

play \ˈlī-kə-nəs, British also ˈli-chə-\ adjective

Illustration of lichen

Origin and Etymology of lichen

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


First Known Use: circa 1657


LICHEN Defined for English Language Learners

lichen

play
noun li·chen \ˈlī-kən, British also ˈli-chən\

Definition of lichen for English Language Learners

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


LICHEN Defined for Kids

lichen

play
noun li·chen \ˈlī-kən\

Definition of lichen for Students

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


Medical Dictionary

lichen

play
noun li·chen \ˈlī-kən\

Medical Definition of lichen

  1. 1:  any of several skin diseases characterized by the eruption of flat papules; especially :  lichen planus

  2. 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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