Ocellar

Part of speech: adjective

Definitions

1. A characteristic of certain organisms indicating a small, simple eye often positioned on the head
2. Pertaining to a particular anatomical feature found in some invertebrates that resembles a rudimentary eye on the dorsal side
3. Describing organisms that possess simple eye structures known as ocelli, often used for detecting light intensity

Etymology: Ocellar comes from the Latin "ocellus," a diminutive of "oculus" ("eye"), so it literally means "little eye." Zoologists use it for the simple eyes of insects, the small light-sensing organs that sit alongside the compound eyes, typically on the top of the head. The word is a technical coinage from the Latin, formed with the adjectival suffix "-ar," and it belongs to the scientific vocabulary of entomology rather than to everyday English. The root "oculus" is the source of a whole family of English words, including "ocular," "oculist," and "binocular," so ocellar is a close relative of the familiar word for the eye. Its diminutive form helps explain its meaning: the ocelli are "little eyes" compared with the large compound eyes beside them. Ocellus itself is also used for the eyespots on butterfly wings and peacock feathers, which resemble tiny eyes.