- The definition of a lichen is a plant found on rocks or trees made of both a specific fungus and a specific algae that help one another.
An example of a lichen is the colored patch growing on a tree branch.
Lichen on tree bark.
- any of various small plants composed of a particular fungus and a particular alga growing in an intimate symbiotic association and forming a dual plant, commonly adhering in colored patches or spongelike branches to rock, wood, soil, etc.
- any of various skin diseases characterized by papules and enlarged skin markings
Origin of lichenClassical Latin ; from Classical Greek leichēn, probably ; from leichein, to lick
to cover with lichens
- A composite organism made up of a fungus, usually an ascomycete, that grows symbiotically with an alga or a cyanobacterium and characteristically forms a crustlike or branching growth on rocks or tree trunks.
- Medicine Any of various skin diseases characterized by patchy eruptions of small, firm papules.
transitive verbli·chened, li·chen·ing, li·chens
To cover with lichens.
Origin of lichenLatin līchēn, a kind of plant, from Greek leikhēn, from leikhein, to lick; see leigh- in Indo-European roots.
common orange lichen