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"Fenestella. In Roman Catholic churches, a niche on the south side of an altar, containing the piscina, and frequently also the credence." -Whitney, 1911

Fenestella in the Church of Norrey

"Fenestella. In Roman Catholic churches, a niche on the south side of an altar, containing the piscina,…

A circular window, divided into compartments by mullions and tracery radiating from a centre, also called Catharine-wheel, and marigold-window.

Rose Brickwork Window

A circular window, divided into compartments by mullions and tracery radiating from a centre, also called…