Quiz: Remember the definition of mal de mer?
1840, of faces. Related: Squinched; squinching.
The tilde, a sinuous diacritical mark (1980s+ Computer)
in architecture, any of several devices by which a square or polygonal room has its upper corners filled in to form a support for a dome: by corbelling out the courses of masonry, each course projecting slightly beyond the one below; by building one or more arches diagonally across the corner; by building in the corner a niche with a half dome at its head; or by filling the corner with a little conical vault that has an arch on its outer diagonal face and its apex in the corner