noun
lichen
LYE-kuhn/ˈlaɪkən/
An organism formed by a fungus living together with algae or cyanobacteria.
Pale green lichen grows across the surface of the rock.

Etymology
Greek leichen originally meant “what eats around itself,” probably connected with leichein, “to lick.” The name thus presents the organism through an image of eating around itself.
In context
… those who can find lichen are better off reindeer have adapted and so are able to gather high energy food like this
More examples
- She photographs the orange lichen on an old fence post.
- Many lichens grow slowly and survive long periods without rain.
- This lichen contains a fungus living together with algae.
Forms
lichen · lichens