noun🔗ShareAny of many symbiotic organisms, being associations of algae and fungi, often found as white or yellow patches on old walls, etc."The old stone wall was covered in patches of green, gray, and yellow lichens. "organismbiologyenvironmentnatureplantChat with AIVocabulary GamePractice Reading
noun🔗ShareSomething which gradually spreads across something else, causing damage."The lichens of graffiti gradually covered the brick wall, making it look unsightly. "biologyplantenvironmentnatureorganismChat with AIVocabulary GamePractice Reading
