oeillade (n.)

word-forming element denoting an action or product of an action, via French, Spanish, or Italian, ultimately from Latin -ata, fem. past-participle ending used in forming nouns. The usual form in French is -ée. The parallel form, -ade, came into French about the 13c. via southern Romanic languages (Spanish, Portuguese, and Provençal -ada, Italian -ata), hence grenade, crusade, ballad, arcade, comrade, balustrade, lemonade, etc.

This foreign suffix ade has been so largely imported, and at a time when the French language had still a certain plastic force, that it has been adopted as a popular suffix, and is still employed to form a crowd of new words, such as promenade, embrassade, glissade, bourrade, &c. [Brachet, "Etymological Dictionary of the French Language," Kitchin transl., Oxford, 1882]

Latin -atus, past-participle suffix of verbs of the 1st conjugation, also became -ade in French (Spanish -ado, Italian -ato) and came to be used as a suffix denoting persons or groups participating in an action (such as brigade, desperado).

Proto-Indo-European root meaning "to see."

It forms all or part of: amblyopia; antique; antler; atrocity; autopsy; binocle; binocular; biopsy; catoptric; Cyclops; daisy; enoptomancy; eye; eyelet; ferocity; hyperopia; inoculate; inveigle; monocle; monocular; myopia; necropsy; ocular; oculist; oculus; oeillade; ogle; ophthalmo-; optic; optician; optics; optometry; panoptic; panopticon; Peloponnesus; pinochle; presbyopia; prosopopeia; stereoptican; synopsis; triceratops; ullage; wall-eyed; window.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit akshi "the eye; the number two," Greek osse "(two) eyes," opsis "a sight;" Old Church Slavonic oko, Lithuanian akis, Latin oculus, Greek okkos, Tocharian ak, ek, Armenian akn "eye."