ˈ ̷ ̷ˌ ̷ ̷ noun
1.
a. : a simple visual organ in many invertebrates that consists of pigment or pigmented cells covering a sensory termination : ocellus
b. : a small pigment body in various unicellular algae that is supposedly sensitive to light
2.
a. : a usually small spot of color (as on the wings of certain butterflies)
b. : a darkish area around the hilum of a seed (as some beans and cowpeas)
3. : any of several fungous diseases of plants characterized by yellowish oval lesions on the leaves and stems ; especially : a disease of sugarcane and various other grasses caused by a fungus ( Helminthosporium sacchari )