Scuncheon

Part of speech: noun

Definitions

1. The inner face or reveal of a wall surrounding a door or window frame, forming the sides and top of the opening
2. The interior surface of masonry or wall material that lines the thickness of a doorway or window aperture
3. The inward-facing wall surface that borders and frames a window or door, spanning the depth between outer and inner wall surfaces

Etymology: In building, a scuncheon is the splayed, angled inner edge of a window or door opening, the surface that runs from the wall face in toward the frame. The word is an old architectural term, and its shape reflects the job the surface does: it widens the opening so more light gets in and the frame sits within a sloped reveal. The word appears in Middle English, and its likely source is Old French "escoinçon," a derivative of "escoin," meaning corner. The connection to "corner" fits the sense of an angled face set into a wall. The exact pathway and the precise date of entry into English are less certain, so treat those details as approximate. Because the term belongs to a specialised trade vocabulary, it rarely appears outside architectural and historic-building writing.