Architecture Terms – O A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Photo by Courtney Cook, via Unsplash ObeliskA tall, four-sided monolith (made of one large block of stone) with a pointed top. Photo by Nick Fewings, via Unsplash Oculus WindowRound windows, openings, and skylights that are located at the top of a dome. Photo by Aa Dil, via Pexels Ogee ArchA popular arch shape that consists of two ogee curves opposite of one another that was used frequently in late Middle Ages and England in the early fourteenth century. Photo by Andreas Brunn, via Unsplash OrnamentAny kind of decorative piece on a building that doesn’t have a structural purpose.