Channeled strips of lead, zinc, or other metal used to bind glass pieces within a design. (See Leaded Glass.)

Cathedral Glass

Describes transparent glass that is monochromatic—i.e., single color sheet glass, with smooth or textured surfaces.

Copper Foil

Thin, narrow strips of adhesive-backed copper tape used to wrap the edges of glass pieces that have been cut to fit a pattern. Once wrapped, solder is applied, bonding the glass pieces together. Assembling a stained glass project in this manner is called the “copper foil technique.” Louis Tiffany is credited with its development.

Dalle de Verre

An art glass medium in which dalles are broken into pieces with a carbon hammer and set in an epoxy base to adhere them in a decorative design. Dependent on large scale for best appearance, they are primarily used in architectural applications such as church walls.

Drapery Glass

Glass sheets with multiple dramatic folds, likened to those in hanging drapes.


Glass of one color with a very thin layer of another color on one side. Flashed glass is often used for etched or sandblasted glass art. When sections of the thin color layer are removed, the base color shows through.


Chemical agent (liquid or paste) used to facilitate the flow of solder and prevent formation of oxides during soldering.


A piece of glass that has been cut and faceted or press-molded into a geometric shape like a jewel. Often incorporated into leaded glass artwork.

Leaded Glass

  1. Sheet glass pieces joined with metal strips, usually made of lead, called “came.” Solder is applied to the joints of the came to bond the work together.
  2. Glass containing lead as a raw material (as in “leaded crystal”).

Opal or Opalescent

Said of any glass into which a material has been introduced at the raw materials stage (usually fluorine or phosphorus) which causes a degree of crystallization to occur, and creates opacity in the glass. Reflected light is colorless, therefore white. The degree of opacity (and “whiteness”) is variable depending upon composition and temperatures used in the manufacturing process. Commonly then, white glass is called “opal.”

  1. Solid Color Opalescent Glass: Glass which is both colored and crystallized, creating a single color sheet, more opaque than a cathedral. Sometimes called “opaque”.
  2. Mixed Opalescent Glass: White glass (opal) mixed with one or more other colors to create a variegated, multi-colored sheet. Light transmission varies with composition. Also called “variegated opalescent,” and sometimes “streaky”.

Painted Glass

Glass on which special paints (containing frit) have been applied in illustration or decorative pattern and then heated in a kiln to a temperature high enough to fuse the pigments permanently to the glass surface. The modern version of the original medieval “stained glass.”


A mouth-blown piece of glass that has been spun into a circular shape, often irregular.

Seedy Glass

Glass in which air bubbles are entrapped. Air or gas is injected into the molten glass prior to forming the sheet.


A fusible alloy, usually tin and lead, used to join metallic parts. (Or can also be the act of applying it.) Used to bond metals in both the leaded and copper foil techniques of stained glass work.

Stained Glass

Commonly used to describe any colored flat glass or any object made of such glass joined by metal strips. The term originally applied to colored or clear flat glass cut to fit an artist’s design, on which details were painted in pigment with a brush. The glass pieces were then heated in a kiln or oven to bond the pigment to the glass surface. This firing makes the painted detail as durable and permanent as the glass itself. Most religious windows from medieval times until this century were executed in this manner, and so the term came to be used first for any architectural application, and then for any design in colored flat glass. It is now universally accepted as a convenient general term to define the art, the craft, and the industry.