of Stained Glass Terms


Acid Etching
Use of hydrofluoric acid to dissolve the surface of the glass; this is used often on FLASHED GLASS to remove a layer of color, revealing the base layer of glass.
Antique Glass
Mouth-blown glass, made by the muff method, in which a tube of glass is blown, then split lengthwise and opened to create a rectangular sheet.
Architectural Glass
Stained glass designed, made, and installed to harmonize with the structure and function of a building.
Steel or iron framing member within the window opening which supports stained glass panels.


Beveled Glass
A decorative glass, usually clear, in which the edges of the glass have been angle cut (beveled). As light passes through the beveled part of the glass, it acts as a prism and will create brilliant highlights and small rainbow color effects.
Braces, Rebar, Or Saddlebars
A flat or rounded steel bar that is anchored in the framing on the side of a window panel and attached by solder or wire ties to the lead joint across the panel. Its purpose is to strengthen the window and hold it in a flat plane. In a window that has begun to bulge, the bulging is usually reduced before a new brace is applied.
Broken or Shattered Glass
A glass that has been so broken or shattered that is cannot be retained and must be replaced.
Buckle and Bowing
Descriptions for condition of lead CAME matrix, seen when saddle bars and structural support fails, windows appear to ‘sag’.
Badger, Badgering
1. Wide, flat brush made of badger hair, used for blending MATTE PAINT; also called a blender.
2. The process of blending a MATTE using a badger brush.
Blender, Blending
Bull's Eye
The raised center portion of a glass CROWN, from which the PONTIL was detached.


Extruded, cast, or milled H-profile metal strip, usually made of lead, sometimes of zinc, copper, or brass, used to hold pieces of glass together to make a stained glass window (archaic: CALME, CALM).
Full sized drawing for a window.
Using SANDBLASTING to create areas of varying depth on plate glass to simulate three-dimensional surfaces.
A window which opens on a vertical pivot at the edge of the SASH.
Cathedral Glass
A rolled glass that can be clear or patterned. It is usually one color per sheet and transparent like ANTIQUE GLASS. It can have regular surface patterns impressed into it by the surface textures of the rollers. It lacks the character and beauty of ANTIQUE GLASS.
The material used to waterproof the edges of a window section, seal it into its frame, and often to seal the frame into the building. It is also often called a sealant.
Liquid waterproofing compound.
U-profile metal strip made of lead, zinc, copper or brass, usually used to frame PLATES or autonomous PANELS.
Cold Paint
Any unfired paint used to decorate stained glass.
Confetti Glass
Glass in which chips of glass of other colors are incorporated.
Copper Foil
Thin, narrow strip of copper, usually with adhesive backing, used to join pieces of glass.
Cracked Glass
A cracked glass that can be sealed so as to retain the original glass.
Crown Glass
Hand-blown glass made by blowing a globe, which is then opened at the base and spun, forming a circular sheet of glass with a BULL’S EYE at its center.


Dalle De Verre
A French tern (“paving stone of glass”) for an inch (or more) thick slab of stained glass. It is shaped with epoxy or cement in a window. Their faceted surfaces break the light into textures and patterns. Also called Faceted Glass.
Divider Bars
Metal T-shaped bars with stops that are used to divide and support stained glass panels and protective covering panels.
Double Glazing
This term usually means two individual layers of glass separated by a dead air space. Any window with a protective storm covering would be double-glazed. It also used to mea plating.
Double Hung
Windows where the SASH slide vertically in their FRAMES.
Drapery Glass
OPALESCENT glass which is manipulated during its manufacture to form similar in appearance to cloth.
To cover a crack during repair, a flange of lead is applied over the crack, tucked under adjoining leads and soldered in place. This procedure has generally been replaced with either edge gluing or a thin foiled line.


Opaque, colored glass paint made essentially of powdered, colored glass.
A clear drying glue composed of resin and hardener, generally mixed in equal parts. Its uses include gluing glass to glass or in construction of Faceted stained glass (Dalle-de-Verre).
Decoration on glass, made by: 1. SANDBLASTING, or with 2. ACID.


Faceted Glass
A more contemporary approach to decorative glass, it consists of roughly cut pieces of glass (about one inch thick) that are bound into panels with concrete, or more often, an epoxy resin. Rarely is any painting used on faceted glass windows. Instead, the design if the window panel is formed in the manner of a mosaic by the combination of the different sizes and colors of the glass and the negative space of the epoxy matrix. Faceted glass can be especially effective in large monumental opening.
Favrile Glass
Trademark of the Tiffany Studios: glass is highly iridized, design for use predominantly in glass objects and vessels; term is used erroneously to describe iridized glass in stained glass windows.
Narrow border(s).
Fire, Firing
Process of placing newly painted glass in a kiln to heat it to a temperature at which the glass paint melts and fuses to the surface of the glass.
In a CAME, the parallel legs of the H-profile. (See MENDING LEAD)
Flash(ed) Glass
Colored ANTIQUE GLASS in which a pale-colored or clear base layer is coated during blowing with a thin layer of darker color.
Supporting elements for PANELS or SASH, which encompass a window opening.
The technique of adhering glass to other surfaces using heat, generally in a kiln. The degree of attachment ranges from a point where they are tacked together, but still two separate pieces; to where the pieces are fully embedded into the bottom glass layer. It also means the heating of painted glasses until the paint bonds with surface of the object.


A mixture of silica (sand), ash, soda, lime and colorants, which are melted, then cooled into a non-crystalline, inorganic super-cooled liquid.
Glass Paint
See COLD PAINT, ENAMEL, GRISAILLE, SILVER STAIN, VITREOUS PAINT; any of a number of materials used to decorate glass; it does not impart color to the body of the glass.
Glaze, Glazing
1. Process of installing glass or windows;
2. Process of assembling leaded glass panels;
1. One who installs leaded glass or windows;
2. One who installs glass into FRAMES or SASH;
(French, Grey)
1. Black, brown, grey, or other dark-colored VITREOUS PAINT, used to decorate glass;
2. Windows of clear glass decorated primarily with this paint, using little or no colored glass;
Groze, Grozing
Process of modifying shapes of glass pieces by chipping away the edges, using either grozing pliers, grozers, the notched side of a glass cutter, or, archaically, a notched iron rod.


Center of CAME: the bar of the H-profile.


A comprehensive plan for the subjects of works of art, not necessarily Christian.
Inset Into Existing Frames
The act of cutting individual patterns of a protective covering material and setting them into an existing frame pattern or tracery. This is done most often when a window has an impressive appearance, and covering it in any other manner would disturb the architectural integrity of the exterior appearance.


Cast or chipped faceted glass pieces.


A decorative glass technique in which two or more layers or glass are glued together to form the design.
Narrow vertical divisions of a window having a pointed Gothic arch at the top, used singly or in multiples for form a larger Gothic window.
Soft, malleable metal used in CAME.
Lead Line
1. In window design, line which indicates placement of CAME.
2. Pattern of caming in a window.
Leaded Glass
The traditional decorative glass technique that is used primarily in window openings, and as decorative inserts in doors, furniture, and lamps. It consists of glasses (colored or clear) about 3/16” thick that are bound by lead CAME to form a decorative design.
Process of GLAZING, or assembly of leaded glass panel.
Glass-filled opening between MULLIONS of a window.
Light Leaks
Gaps between glass and lead, or panel and frame, through which daylight can be seen.
Low Fire Enamel Technique of Painting on Glass
This type of glass painting differs in two major ways from the traditional trace and matte technique: it is fired at a lower temperature and the paint is made of colored enamels that are very lightly tinted or clear. In Trace and Matte, the color is in the glass. Being a low fire technique it does not fuse as well as a traditional trace and matte painting, and often will fade or peel after 50 years.
Semi-circular window.


Matte Paint, Matting
1. Washes of GLASS PAINT, usually GRISAILLE, usually applied to the interior surface of the glass; used for shading;
2. Process of applying washes of GLASS PAINT;
Mending Lead (also DUTCHMAN, FLANGE, or STRAP LEAD)
Full CAME or flange of CAME (separated from the HEART of the CAME) inserted between broken pieces or applied to the surface of the broken pieces or applied to the surface of the broken piece of glass.
Missing Glass
Glass that has been completely removed from the lead.
FRAME member, usually vertical, diving frame into LIGHTS.
A muntin is a strip (either real or illusory) separating panes of glass. Because it was impossible or prohibitive to manufacture larges sheets of glass prior to the 20th century, big expanses of windows were achieved by holding many, smaller panes of glass together by muntins. A true muntin is a strip of wood or similar materials completely separating panes of glass. In the modern world, the illusion of muntin is created by sandwiching thin strips of aluminum or plastic between double-paned glass, or by affixing these grilles onto the outside of the glass.


Norman Slab Glass
A type of ANTIQUE GLASS in which the molten glass is blown into box-shaped molds, and when it solidifies is cut into rectangles. These slabs are thicker in the center and thinner along the edge, giving each piece a great depth of color and beauty. Unfortunately, Norman slab glass is not made anymore.


Circular window, not divided by spokes or radil.
Opalescent Glass
Milky, opaque glass, often of more than one color, developed in late 19th century American and popularized by Louis Comfort Tiffany.


Painted Glass
Any glass in which paint has been applied for design purposes and the glass baked to make it more permanent. There are two basic types of painted glass used in stained glass: the traditional Trace and Matte technique, and the Low Fire Enamel technique.
Unit of leaded glass.
1. Surface film produced by chemical action of air pollutants, dirt, and water on glass over the course of time;
2. Chemicals applied to glass, CAME, or copper foil to induce the appearance of aging.
Perimeter Framing
The metal perimeter or a frame of a window or a protective covering.
Plate, Plating
Layered piece(s) of glass.
Pontil (or Punty)
Iron rod to which blown globe of hot glass is attached to spin a CROWN.
Protective Covering
A covering on the exterior of the leaded stained glass windows that protect the windows from the weather, and from accident or vandalism. It also can help insulate the building. Protective coverings are usually made of float glass or plastic.
Thick waterproofing or settling compound.


Regular geometric shapes of glass, used in a repeating design.


Releading or Glazing
The act of completely disassembling a leaded window, cleaning the glasses, and reassembling the window with new lead. Releading is needed only when the lead can no longer perform its function of joining and supporting the glasses in a window. Depending upon the condition there are some windows that need reloading in 100 years; while there are windows in Europe that have lead that is 500 years old.
Rose Window (also Wheel Window)
Circular window divided by radial mullions, usually in a floral or wheel pattern.
Roundel (or Rondel)
Round clear panel, composed of a single piece of glass, (see bullseye) sometimes with borders, painted with a complete scene, usually in GRISAILLE and SILVER STAIN.


Saddle Bars
Round or flat, iron or steel support bars, which are set into the SASH or FRAME, crossing the window opening, usually on the inside of the stained glass panel, to which the stained glass is fixed with TIE WIRES, to prevent bowing and sagging.
Process in which sand under very high pressure is directed at glass covered with a STENCIL; those areas not covered by the stencil are etched or frosted.
The operable or removable part of a window.
Small bubbles in ANTIQUE GLASS.
Silver Stain
A type of GLASS PAINT composed of silver nitrate or silver chloride, applied to the exterior surface of glass; when fired, it stains the glass a yellow to golden-orange color.
Mixture of lead and tin, melted with a soldering iron to join the ends of CAME or the seams of copper foil.
Spring Line
The point in an arch at which the arch begins.
Stained Glass
1. Leaded glass PANELS;
2. Painted glass, or painted glass PANELS;
3. Glass colored during its manufacture.
Creation of repeated designs by painting or etching, using a cutout pattern.
Type of MATTE in which the tips of a BADGER are repeatedly touched to wet GLASS PAINT.
Repair-using materials foreign to the window, such as glass from another, wood, lead, tar, etc.
Strap Lead
Straightening Bulges
Straightening a bulge means that the probable cause of the bulge will be determined and eliminated and the leaded panel will be restored to as flat a plane as possible, eliminating the pressures of the glass and the lead. This does not always mean the bulged area will be totally flat plane as measured by a carpenter’s level. For example to create special visual effects many leaded windows are constructed with glasses of varying thickness. Examples would include Norman Slab Glass, pressed jewels, and panels that are plated with extra layers of glass. In such cases the panels or the glass will always have a slightly bulged appearance.
Support Bars


Iron, steel or aluminum support bars having a T-profile, set into the FRAME and upon which the PANELS are set.
Tie Wires
Copper wires or lead strips soldered to the stained glass PANELS to be wrapped around saddle bars and twisted closed.
Trace and Matte Technique of Painting on Glass
In this technique the color is inherent in the stained glass before any painting is applied. For example, if the particular piece of glass is to be a face, a flesh colored piece of glass will be utilized. A special high fire glass paint (usually shades of black or brown) is applied to the colored glass to control the flow of light. The darkness or lightness of this paint is what forms the designs on the glass. The glasses are then fired at high temperatures to fuse the glass and the ground glass-based paint. This is the same traditional type o glass appointing that has been used for over 10,000 years.
Trace, Trace-Line
Dark, opaque paint line, usually applied to the interior surface, used to delineate details.
Ornamental framework at the top of a window opening, usually one of the Gothic style.


The part of a stained glass window that opens to allow for ventilation. In older windows it is usually made of steel or wood. In most new windows it is aluminum.
Vitreous Paint
Paint composed of ground glass and metallic oxide pigments, applied to glass for detailing and enhancement, fired in a kiln to melt and fuse with the surface of the glass.


Stiff, brittle metal used for CAME; not as common as lead CAME.
Zinc Came
An H shaped zinc strip that is used similar to lead CAME. Stiffer than lead CAME, it can give greater structural support but is very difficult to work with—especially on small, intricately curved pieces of glass. Today it is most often found in door panels when heavier beveled glass is used.