Definitions

1. noun

a plural of periscope, especially in the context of ancient Greek or Roman architecture, referring to a structure resembling a periscope

“The ancient Greek temple featured a periscii that allowed sunlight to enter the dark interior.”

2. noun

a plural of periscope, referring to any structure with a series of apertures or windows for observing the surroundings

“The periscii on the space station allowed astronauts to view the Earth from various angles.”