- a sensory organ of lower animals, having a light-perceiving function.
- an eyelike spot, as on the tail of a peacock; eye.
- a disease of plants, characterized by elliptical lesions on the leaves and stems, stunting of growth, and rotting, caused by any of several fungi.
- a small area of light-sensitive pigment in some protozoans, algae, and other simple organisms
- an eyelike marking, as on the wings of certain butterflies
