Abstract Design

  1. A design whose forms have been reduced or modified from representational forms.
  2. A design using non-representational forms.

Ambient Light

The existing, diffused light. Light coming from many directions.

Antique Glass

Mouth-blown sheet glass with the irregularity of "medieval" glass. Glass blown into a large cylinder that is cut, opened, and flattened into a sheet. Variations of antique glass may include seedy, crackle, flashed, opal, opak, reamy and streaky. "Antique" refers to the technique—not the age.


The semi-circular termination of the east end of the chancel or chapel.

Architectural Glass

Ornamental, decorative glass (e.g. stained, leaded, laminated, fused, etc.) glass designed, made and installed to harmonize with the structure and function of a building.


A metal divisional bar or bars making a framework for supporting stained glass, usually fixed into a wall. Also used within concrete for strengthening.

Art Deco

The style of work produced in the early twentieth century that reached its apex at the Exposition Internationale des Arts Décoratifs et Industriels Modernes held in Paris in 1925. Characterized by bold geometric shapes, streamlined and rectilinear forms.

Art Glass

A general term for any decorative glass, panel, or window made with opalescent, iridescent, or pattern glass.

Art Nouveau

French for "The New Art," an art movement popular in the 1890s and early 1900s in Europe and America. A busy, decorative style characterized by flowing vines and flat shapes (as seen in Tiffany glass) and undulating lines.


A radiant light around a head or body of the representation of a sacred person.

Autonomous Panel

A non-architectural stained glass composition.

Awning Window

A window whose sash is hinged at the top and projects out when open.


A separate room or building of a church containing the font.


A solid metal bar, often steel, held by copper wire ties or solder directly to the interior of stained glass windows for support and reinforcement.


  1. Machine made to imitate reamy glass.
  2. A style of art of the seventeenth and eighteenth centuries characterized by overblown realism and curved figures.


An artistic style derived from the principles of a German school of architecture and design founded in 1919, and terminated prior to World War II.


  1. The space between columns.
  2. One complete transverse unit of the architecture, interior or exterior.

Bay Window

Three or more window units attached to a building so as to project outward.


Cut and polished edge usually on plate glass at an angle other than 90š, done in stages with roughing, smoothing, cork and felt wheel polishing.


Applying a thin layer of putty or sealant to the flat surface before installing a window.

Came (Calms)

Metal strips, generally "U" or "H" shaped, used to hold glass pieces together to form a stained glass window. Originally lead, but zinc, brass copper and lead ores are also used.


An architectural framing device to enclose a figure or scene.


Full-size working drawing showing detail of leading and painting.

Casement Window

A window sash hung by hinges and fastened to the window frame.

Cathedral Glass

Machine rolled transparent colored glass.

Cats Paw

Opalescent glass with a mottled appearance that suggests cat paw prints.


The east portion of the church set aside for the clergy and choir.


"U" shaped groove in the came in which the glass sits.

Chipped Glass

A technique where glue pulls the surface of the glass, causing it to chip.


The upper part of the nave above the side aisles of a church.

Color Selection

The very careful choice of colored glass, under natural light, so that an exact choice or replacement is possible. In restoration work, a large inventory or "library" is essential so that when pieces are replaced, the selection is not constrained or limited. Literally thousands of colors, textures, and densities are possible.

Colored Glass

Glass with an obvious tint, caused by mixing minerals throughout the hot glass

Commercial Glass

Clear, heavy glass with a pattern pressed on one side.


The overall design of a finished piece containing balance of color and linear flow.

Copper Foil

  1. The mil-thickness copper material, often adhesive backed, used to join separate pieces of glass.
  2. The technique of joining pieces of glass where foil is centered on the edge of each glass piece, then bent over the edge to cover a very small portion of the back and front faces of the glass. Pieces are abutted and solder is melted over the exposed foil surfaces, causing the foil-covered glass edges to become joined.

Crackel (Craquel) Glass

Antique glass with cracked texture which has been intentionally introduced during the cooling process.


Cross shaped.


The projecting points formed by the intersection of two segmental arcs or foils.


Machine-drawn antique glass.

Dalle de Verre

A thick slab of cast stained glass that is cut or broken and cemented into a panel with an epoxy adhesive matrix.


Visible opening size.

Dichroic Glass

Space-age application of super thin, clear layers of metal oxides which allows for either transmitted or reflected color, depending on the viewer's viewing position.

Double Glazing

The use of two pieces of glass, one in front of the other, with an air space between for insulation.

Double Hung

A window consisting of two sashes of glass operating in a rectangular frame. Both upper and lower halves slide up and down to open.

Double Strength Glass

One-eighth inch thick glass. Strength refers to thickness.


The painting on glass that defines the drapery robes of figures, usually Biblical.

Drapery Glass

Heavily manipulated, folded or rippled glass that forms "drapes" that may be one inch or more thick.


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 copper foiled line.

Dry Glazing

A method of securing glass in a frame with just resilient gaskets.

European Antique

Mouth-blown antique glass from Europe and England.

Exterior Glazed

Glass set from the exterior of the building.

Exterior Stop

The molding that holds the light on the exterior of the frame.


The front of a building.

Faceted Glass

Stained glass windows made of Dalle glass and a matrix.


Iridescent glass patented by Louis Comfort Tiffany in the 1894, produced by the exposure of hot glass to metallic fumes and oxides,characterized by a “rainbow” effect when seen from different angles.

Figured Glass

Cut on a wheel (brilliant), but also etched and pattern glass.


A thin strip, or border of glass.


The arrangement of windows in a structure.

Fixed Window

A window permanently fastened to the frame.

Flashed Glass

Sheet glass, usually clear, with a thin layer of colored glass on one side.

Flemish Glass

Clear cathedral glass with a large wavelike pattern on both sides.

Float Plate Glass

Flat glass manufactured by floating the ribbon of drawn, molten glass on a long bath of molten tin, and fire-polishing the upper surface, yielding a smooth, polished surface on both sides.


French new antique glass, a machine-drawn antique glass.

Frosted Glass

Glass with a white translucent surface resulting from sandblasting or etching.


French semi-antique, a machine-drawn antique glass.

Full Antique

Mouth-blown antique sheet glass.


A style, generally referring to architecture, found in western Europe from 12th through 16th centuries.

Glass Etch

Any of several compounds that permit the frosting of glass.

Glass Globs

Thick, round pieces of glass, from .5" to 2" in diameter.

Glass Jewels

Small pieces of clear or colored glass that have been faceted, molded or domed.

Glass Paint

Vitreous paints composed of metallic oxides and ground glass in a liquid vehicle and then fired on glass.


The process of assembling pieces of glass and lead to make a window.

Glue Chip

The application of heated animal glue to sandblasted glass that, when dry, chips off, leaving a crystalline or icy look.

Goethe Glass

A clear blown glass without seeds or striation, just a slight surface distortion from the blowing process, similar to old window glass.


German new antique, a machine-drawn antique glass.

Granite Back Glass

Cathedral glass with a rolled bumpy, rough texture on one surface of the glass.


A panel or window of clear or light-colored glass painted with geometric or foliate designs. Sometimes used to refer to glass paints.


A phenomenon where light-colored glass, when surrounded by darker glass, seems to spread beyond actual boundaries, creating a halo effect.

Hammered Glass

Cathedral glass with a tiny, tight, uniform pattern of round, smooth knobs.

H Bar

An "H" shaped metal bar used as a support between two sections of a panel.


A window whose sash is hinged at the bottom.


A comprehensive plan for the subjects of works of art, not necessarily Christian.


The part of a window that is non-movable.

In Situ

In position.


A surface treatment on glass that has a shiny, mother-of-pearl look.

Isothermal Glazing

System of protective outer glazing that inhibits conductivity of heat from the exterior to the interior surface of the complete window unit.


The upright surface forming the side of a window.


Smooth, faceted, pressed, or chipped pieces of glass made to look like precious stones, used as inserts in decorative glass windows

Laminated Safety Glass

Two sheets of clear glass bonded together with a sheet of clear plastic in the middle.


A long, narrow window with a pointed arch.

Lead Came

Extruded lead channel with an H or U cross section to hold the glass in the panel.

Lead Line

A line produced on a full-size drawing of a leaded window to indicate the position of the lead came.


Pieces of clear glass held together in a web of lead cames.


An opening through which sunlight is admitted; also a section of a large window, usually found in series divided by mullions.


Opaque material used as a cement to hold the glass in place in a faceted panel.


A small, bordered picture area of a window, primarily of the twelfth and thirteenth centuries.


A time period that included the Romanesque and Gothic periods, also called "The Middle Ages," from about A.D. 500 to 1500.


A mineral that flakes into thin, translucent sheets; famously used as a material for lampshades in copper lamps, like those by Dirk Van Erp.

Mouth Blown

Glass produced by forcing air, by mouth, through a blowpipe into molten glass.


The vertical strip dividing the panes of a window.


A horizontal strip dividing panes of a window.


The vestibule, or entrance of a church.


The long, central portion of a church auditorium.

Negative Painting

A reverse glass-painting technique done on the back side of glass, in which the detail is painted before the background. Usually done with unfired paints.

Negative Space

Any part of a glass window through which no light is transmitted, usually the dark lead line, matrix area of a window and/or an opaque painted area.

Neo Gothic

Nineteenth Century revival of Gothic style.


Not representing any object. Not realistic.

Norman Slabs

Glass blown into a rectangular mold and cut apart on the corners, resulting in square or rectangular pieces that are thin at the edges and thick in the middle.

North Side

The north or left side of a church is traditionally the side of darkness and the Old Testament, which is often reflected in the subject matter and colors of these windows. It is not necessarily compass north.


Non-transparent glass resulting from painting, sandblasting or acid etching.


A circular window without stone tracery. Also called Occhio, Occhi, Oculu.


White opal flash on a colored antique.

Opalescent Glass

Non-transparent or semi-opaque machine-rolled glass often with two or more colors streaked together.

Opal Glass

A glass with a milky or resinous appearance.


Not transparent.


Occupational Safety and Health Administration, charged with ascertaining that employers provide their employees a place of employment free from recognized hazards that are causing or are likely to cause death or serious harm to their employees.

Paint (For Glass)

A mixture of finely ground glass, metallic oxides and a liquid mixing agent, such as water and gum arabic, used for painting on glass. It has to be fired for permanent adhesion.

Palladian Window

A window with three panels, the center panel being wider, with an arched top.


Unit of stained glass leaded together and made to fit an opening in the framework of a window. May be of any shape.


Machine-rolled sheet glass with an embossed overall pattern; usually in “white” (clear) glass

Pivoted Window

A window that swings open on pivots at the top and bottom.

Plate Glass

Clear window glass that exceeds 3/16" in thickness


Putting a second piece of glass over a portion of a panel to alter the color, or for reinforcing old glass.


Small flat triangles of zinc used to hold glass in a wooden window sash.


Glass windows or panels in clear and/or colored glass in geometric patterns to complement the architectural style known as Prairie; usually held in place with zinc rather than lead, which produced a crisper look.


The east end of the church housing the altar.


Diamonds or rectangles of glass leaded together in a lattice design.


Small opening in Gothic tracery having four arched sides. Also called arabesque.


An "L" cut all around the perimeter of the window frames, against which the stained glass panels are installed.


Full antique glass with cords of wavy, irregular surface and large bubbles.

Reed Glass

Clear commercial glass with half circle ribs (refrigerator shelf glass).

Reflected Light

Light being reflected off the surface of glass as opposed to transmitted light.


A "U" shaped groove in wood or stone used for setting a window.

Reinforcing Rod

Galvanized steel rods or bars used to prevent a stained glass window from sagging or bowing.


The reintroduction of classical styles in the 15th and 16th centuries.


The screen at the back of the altar.

Ring Mottled

Opaque glass with spots of a translucent color.

Ripple Glass

Machine-rolled glass, the rippled texture of which is imprinted from the roller.

Rolled Glass

Sheet glass formed by a roller flattening the glass into sheets.


A style founded on Roman principles, most prevalent in architecture in western Europe from the ninth through the twelfth centuries.

Rondel (Roundel)

Round spun disk of stained glass with a punty mark in the center.

Rose Window

A circular window divided by tracery, usually on the large west wall of a cathedral.


Semi-antique glass.

Saddle Bar

A metal bar attached to the inside of a stained glass panel and secured to the window jambs to prevent bulging or sagging, or secondary structural elements set into the window frame and attached to the window panels by solder and copper wires to provide additional bracing and support.


The area of the church where the altar is located.


The technique of blowing abrasive materials under pressure onto the glass surface to etch away part of the glass.

Sand Carving

Abrasive etching done deeper and in layers, creating a sculptural effect.


The window frame.

Seedy Glass

Glass that has tiny bubbles throughout.

Semi Antique Glass

Machine-drawn transparent glass made to imitate the look of antique glass. Also called D.A., S.A., G.N.A., F.N.A. and new antique.


All blocks used as spacers in installing a window.


A printing method of applying paint to glass.

Silver Stain

A mixture containing silver salts, which, when fired on glass, sinks into the glass, causing a permanent color ranging from pale yellow to amber.

Single Glazed

The use of a single thickness of glass in a window.

Single Hung

Window that has a stationary top and a moveable bottom half.

Single Strength

Window glass 1/16" thick.

Slab Glass

Transparent stained glass cast one inch thick.

Slag Glass

Glass with two or more colors in a marble-like pattern; a popular for the glass in Arts and Crafts light fixtures.

South Side

The south or right side of a church is traditionally the side of Light and the New Testament, which is often reflected in the subject matter and colors of these windows. It is not necessarily compass south.

Spring Line

The horizontal line below which the upright sides end and the curve of the arch begins.


Glass that has been melted in a kiln (sometimes in a mold) to achieve undulating and textural effects.

Stained Glass

Historically, leaded windows of glass that have been painted and fired, with or without the application of silver nitrate; today, may refer to any colored art glass.

Stained glass, in strictly technical terms, can be described as an assemblage of variously colored pieces of glass supported in a single flat plane by leads and fixed more or less permanently in a frame of stone, wood, or metal; the design being expressed partly by the arrangement of the shapes of glass and leads, and partly by the addition of glass paint and stains rendered impervious to erasure by being fired into the surface of the glass before leading-up (or glazing). Its essential form is two-dimensional, non-tactile mostly monumental in scale and placed (normally) in non-utilitarian buildings for the purpose of assisting the creation of a special atmosphere as required/requested/commissioned. 

The very phrase stained glass is a stumbling block, for we have a great art form described by words that relate only to one part of its process. Indeed, if by “stained” one means the application of silver oxide to colorless glass to give a yellow color, there are many windows in which this is quite absent; on the other hand, if the word ‘stained’ means the basic coloring of the molten glass—the point at which color ‘strikes’ or becomes fused—‘colored glass would be a more apt description. But it is still rather like describing paintings as ‘painted canvas’ or sculpture as ‘wrought stone’. The term 'stained glass' seems to have come into use around the beginning of the nineteenth century as a contraction of ‘painted and stained glass’; in the Middle Ages it was simply called 'glass' or 'glaziers’ work'; in Germany it is 'Glasmalerie' and in France it is 'vitrail'. However, 'stained glass' has become a term in our language and to try to change it now would only add to the confusion.

—excerpt from "The Appreciation of Stained Glass" by Lawrence Lee

Stationary Stop

The permanent stop or lip of the window sash that holds the panel in place.


Wood or metal flange used to hold a window in place.


Having a color or colors unevenly distributed in sheet glass to form streaks or swirls.

Strength of Glass

Refers to the thickness of glass, i.e., single or double strength.

Support Bars

Iron bars tied to the leaded panel by copper wire for reinforcing.

T Bar

Metal "T" shaped mullions put into a frame opening to support glass panels that will be set one above the other. The T bars receive the weight of each panel and transfer it to the frame.

Thermal Shock

Cracking caused by uneven rapid heating or cooling of glass.

Tie Wires

Copper wires soldered to the panel and twisted around a saddle bar.


The stone framework in a gothic window.

Traditional Design

Motifs and styles handed down from one generation to another.


The transverse section of a church crossing the main nave.


Semitransparent, allowing the passage of light but not permitting a clear view.

Transmitted Light

Light that passes through transparent or translucent glass.

Transom Window

A window above a door.


Admitting the passage of light with a clear view beyond.


  1. A small opening in Gothic tracery having three arcs.
  2. A garland design with three loops.


A picture, carving, etc. with three parts.


The triangular space above a door, sometimes containing a window.

Vitreous Paint

A mixture of ground glass and metallic oxides used to paint on glass.

West End

The west or entrance end of the church is the people's area. Usually the large west wall has the rose window. It is not necessarily compass west.

White Glass

Term often misused for clear glass.

Window Glass

Clear glass.


Cathedral glass containing white cloud-like streaks.

Z Section

A Z-shaped metal extrusion found at the perimeter of the sash.