lichen

 
Pronunciation: /ˈlʌɪk(ə)n, ˈlɪtʃ(ə)n/

noun

  • 1a simple slow-growing plant which typically forms a low crust-like, leaf-like, or branching growth on rocks, walls, and trees: the cedars are festooned with lichen [count noun]: rocks covered with gold lichens
  • 2 [mass noun, usually with modifier] a skin disease in which small, hard round lesions occur close together: patients with oral lichen planus

Derivatives

lichened

adjective
lichen (sense 1).

lichenology

Pronunciation: /-ˈnɒlədʒi/
noun
lichen (sense 1).

lichenous

adjective
lichen (sense 2).

Origin:

early 17th century: via Latin from Greek leikhēn