lichen

• اسم يشير إلى مرض جلدي يظهر على شكل بقع صلبة وسميكة، أو إلى كائن حي تكافلي يتكون من طحالب وفطريات، وغالبًا ما ينمو على شكل قشور أو نموات شجيرية على جذوع الأشجار والصخور أو الأرض العارية.

A noun referring either to a type of skin disease characterized by hard, thick lesions, or to a composite organism (thallophyte) consisting of algae and fungi, typically forming crusty or bushy growths on tree trunks, rocks, or bare ground.

1. Symbiotic organismB2formalscientific

   A composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship, commonly found as crusty or bushy growths on trees, rocks, or bare ground.

   الأشنات

   • The old stone wall was covered in patches of grey and orange lichen.
   • Lichens are often used as bioindicators of air quality.
   • Hikers can find colorful lichen growing on tree trunks in the forest.

2. Skin conditionC1formalmedical

   A term for several eruptive skin diseases characterized by hard, thick lesions that cluster together, resembling the appearance of lichen on rocks.

   الحَزاز

   • The dermatologist diagnosed the patient with lichen planus.
   • Lichen simplex chronicus is a skin disorder caused by repeated scratching.
   • Treatment for lichen sclerosus often involves topical corticosteroids.