Oilette

Oilette - A round opening at the base of a loophole, usually for a cannon muzzle
O"lite - Granular limestone.
Open joint - Wide space between faces of stones.

Oilette: a round opening at the base of a loophole
Oriel or Oriel Window: projecting room on an upper floor, later an upper-floor bay window
Oubliette: a dungeon reached by a trap door ...

Oilette - a round opening at the base of a loophole or arrowloop, usually for a cannon muzzle.
Olite or Oolite - granular limestone.
Onager - Roman name for a Mangonel, literally a "wild ass".

The story is also a glossary of post-medieval Maltese, Turkish and battle argot: langue, allure, gazi, devshirme, tercio, arquebucero, auberge, crenel, barbican, oilette, etc.
Horrific post-medieval religious war by The Seattle Times (Seattle, WA) ...

See also: Merlon, Merlons, Crenel, Medieval, Crenelation