What is the meaning of Lichen?

Any of many symbiotic organisms, being associations of algae and fungi, often found as white or yellow-to-blue–green patches on rocks, old walls, etc.

Something which gradually spreads across something else, causing damage.

To cover with lichen.

lichen

a cryptogamic species of vegetation growing on trees, lichen

an eruption on the skin of men and beasts, a tetter, ringworm

  1. a callous excrescence upon the leg of a horse, used as a medicine

a callous excrescence upon the leg of a horse, used as a medicine

to kick out, to throw out, to sack

to lift (a little)

to get up, to leave (as a guest), to get to one's feet

to lift (fog, mist)

lichen

Source: wiktionary.org