\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.

\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.