tracery

noun, plural trac·er·ies.

1. ornamental work consisting of ramified ribs, bars, or the like, as in the upper part of a Gothic window, in panels, screens, etc.
2. any delicate, interlacing work of lines, threads, etc., as in carving or embroidery; network.

noun plural -eries

1. a pattern of interlacing ribs, esp as used in the upper part of a Gothic window, etc
2. any fine pattern resembling this

n.

mid-15c., “a place for drawing,” formed in English from trace (v.) + -ery. Architectural sense, in reference to intersecting rib work in the upper part of a gothic window, is attested from 1660s. “Introduced by Wren, who described it as a masons’ term,” according to Weekley.