a type of prison building, conceived by the philosopher Jeremy Bentham, to allow an observer to observe all prisoners without the prisoners being able to tell if they are being observed or not, thus conveying a “sentiment of an invisible omniscience”

This word, popularized within academia through the writings of Michel Foucault, was all the rage back when I was in grad school during the early 1990s. The definition above comes from Wikipedia, which has a lot more information about the literal and metaphorical uses of the term. The word pops up in an article in the August 2005 Wired magazine: “Build an arfid panopticon for the convenience of cops and spooks, and you can expect a swift and violent Orange Revolution.”