Tracery \Tra"cer*y\, n. A tracing of lines; a system of lines produced by, or as if by, tracing, esp. when interweaving or branching out in ornamental or graceful figures. ``Knit with curious tracery.'' --Burns.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Tracery \Tra"cer/y\, n.; pl. Traceries (Arch.) Ornamental work with rambled lines. Especially:
   (a) The decorative head of a Gothic window.

Note: Window tracery is of two sorts, plate tracery and bar tracery. Plate tracery, common in Italy, consists of a series of ornamental patterns cut through a flat plate of stone. Bar tracery is a decorative pattern formed by the curves and intersections of the molded bars of the mullions. Window tracery is imitated in many decorative objects, as panels of wood or metal either pierced or in relief. See also Stump tracery under Stump, and Fan tracery under Fan.
   (b) A similar decoration in some styles of vaulting, the ribs of the vault giving off the minor bars of which the tracery is composed.

Source: Webster's Revised Unabridged Dictionary (1913)