ocellus

UK: /ɒˈsɛləs/ US: (ō sel′əs)

WordReference Random House Unabridged Dictionary of American English © 2025

o•cel•lus  (ō sel′əs), n., pl. o•cel•li 

(ō sel′ī). 
1. Invertebrates a type of simple eye common to invertebrates, consisting of retinal cells, pigments, and nerve fibers.
2. an eyelike spot, as on a peacock feather.

• Latin: little eye, diminutive of oculus eye; see -elle
• 1810–20

Collins Concise English Dictionary © HarperCollins Publishers::

ocellus / ɒˈsɛləs/ noun ( -li / -laɪ/)

1. the simple eye of insects and some other invertebrates, consisting basically of light-sensitive cells
2. any eyelike marking in animals, such as the eyespot on the tail feather of a peacock

Etymology: 19th Century: via New Latin from Latin: small eye, from oculus eye

oˈcellar adjective

ocellate / ˈɒsɪˌleɪt/, ocellated / ˈɒsɪˌleɪtɪd/ adjective

ˌocelˈlation noun