Cathedral Glass: Glass sheets for manufacturing leaded glass windows and mosaics. Louis Comfort Tiffany maintained at least one cathedral glass shop in his glass-works, in which a dazzling variety of colors, textures and degrees of translucency was developed. In 1897 Cecilia Waern reported in The Studio that Tiffany maintained an available stock of 200 to 300.

Cire Perdue: The French term for Lost Wax. This is a process in which a model is carved in wax then has a mold built up around it. When this is heated, the wax melts and runs out through small holes in the base of the mold, which is thus left with the exact contours of the original wax model. The mold can them be filled with molten glass or bronze which, on cooling, appears as an exact replica of its original model. Some molds are re-usable, others are destroyed when opened.

Favrile: The Trade Mark registered by Louis Comfort Tiffany in 1894 referring not only to the iridescent glass he manufactured, but also to his other creations, including ceramics, lamps and leaded glass windows. It is derived from “febrile”, an Old English work indicating the product of a craftsman.

Incalmo: A technique that usually results in two distinct sections of color in a vase-like object. It is done by opening out two blown pieces so the lips are identical in diameter, heating and bringing the edges together. The joined piece is then freed from one pipe/punty and further worked. Most commonly a bowl is created and puntied for one piece while the other is still on the pipe and is opened for joining without having to be freed from the pipe. When it is freed, the opening at the pipe becomes the mouth of the piece.