turning piece

American  

noun

1. a wooden pattern for an arch built without centering.

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Etymology

Origin of turning piece

First recorded in 1815–25

Example Sentences

In the case of a semicircular or elliptical arch with 4� in. soffit this turning piece would be constructed of ribs cut out of 4 in. stuff with ties and braces.

From Project Gutenberg

Then, there were other side-scenes not of much account, owing to lack of room, and on each wing a turning piece with three broad flats representing three different subjects.

From Project Gutenberg