Judas window n. an aperture or glass pane that permits safe or surreptitious observation through a door or wall. Editorial Note: This is a variation on Judas hole, Judas trap, or just Judas. (source: Double-Tongued Dictionary)
Further reading
In 1971, when a new public library opened in Troy, Michigan, famous authors and artists were invited to write letters to the city’s youngest readers, extolling the many benefits of libraries. One of the loveliest was from E.B. White, author of...
Judy from Huntsville, Alabama, recalls her stepmother’s words of encouragement: He that hath a horn to toot and tooteth it not, the same shall not be tooted. This faux-formal bit of advice goes back at least to the 1850s. A variation goes:...