Definition: Tricosylic is a term in medicine that refers to a type of disorder where there are three different types of cells (i.e. keratinocytes, hyaline epithelial cells, and macrophages) present in the body. This condition can occur due to various factors including viral infections, autoimmune disorders, or genetic mutations. Tricosylic cells can cause inflammation and damage to other tissues, leading to a wide range of symptoms such as fever, joint pain, and fatigue.