I. ˈlīkə̇n sometimes chiefly Brit ˈlichə̇n noun
( -s )
Etymology: Latin, from Greek leichēn, lichēn, probably from leichein to lick — more at lick
1. : any of numerous complex thallophytic plants that constitute the group Lichenes, that are made up of an alga and a fungus growing in symbiotic association on various solid surfaces (as rocks or the bark of trees), that consist of a branching thallus which is not differentiated into stem and leaves but which may be crustose, fruticose, or foliaceous and which contains algal gonidia embedded in a meshwork of fungal hyphae, and that include organisms important in the weathering and breakdown of rocks and some that are sources of foods or dyes — see ascolichenes , basidiolichenes ; iceland moss , reindeer moss ; archil , litmus
2. : any of several skin diseases characterized by the eruption of flat papules ; especially : lichen planus
II. transitive verb
( -ed/-ing/-s )
: to cover over with or as if with lichens
they lay till all their bones were … lichened into color with the crags — Alfred Tennyson
look down upon the lichened walls of this lovely building — R.M.Lockley
lichened history, an immeasurably vast continuity — R.L.Mittenbuhler