ocellus

This term is primarily used in biological and zoological contexts, carrying a technical register. It describes a specific anatomical structure or a visual pattern, distinguishing it from a complex eye (compound eye) by its inability to resolve detailed images. The term is most frequently encountered in entomology when discussing the sensory organs of insects or the mimicry patterns on lepidopteran wings.

In the context of mimicry, the ocellus serves as a defensive mechanism. The visual "eye-spot" is designed to trigger a fear response in predators by simulating the gaze of a much larger animal, such as an owl or a snake, thereby providing a survival advantage to the organism.