ocularium UK /ˌɒk.jʊˈlɛəɹi.əm/US /ˌɑk.jəˈlɛɹ.i.əm/ noun2 •An elevated mound or "turret", found in some arachnids and other creatures, which contains simple eyes (ocelli). •A slit in a helmet through which the wearer could see.[…] A CLOSED HELMET, with blued surface; the skull-piece has a high roped comb, a deep visor pierced with the ocularium, bevor with annular piercings […] — 1901 formsocularia
