Other forms: lichens
Lichen is a crusty growth on rocks and bark, part fungus and part alga. Grey lichen, lichen on the wall, lichen-covered stone.
It is two organisms living as one, the fungus providing shelter and the alga making food. It grows a fraction of a millimetre a year and dies where the air is dirty, which makes it a living measure of pollution.
1nounlichenA crusty growth on rocks and bark, part fungus and part alga.
“The old gravestones were covered in grey and yellow lichen.”
lichen is an organism.
Greek leichen comes from leichein, to lick, from the way the growth spreads across a surface.
Proto-Indo-European
*leyǵʰ-
Ancient Greek
λειχήν
Latin
līchēn
English, today
lichen
Built from
Latin līchēn, from Ancient Greek λειχήν, from λείχω (“to lick”). Originally used of liverwort; the modern sense first recorded 1715.
Etymology from Wiktionary, CC BY-SA