Abstract
Abstract art is defined as art that has no reference to any figurative reality. In its wider definition the term describes art that depicts real forms in a simplified or rather reduced way - keeping only an allusion of the original natural subject.

Anheal
To heat glazes or glass and then slowly cool them to toughen and reduce brittleness.

Artist's proof
Technically one of the first proofs in a limited edition of original sculptures, but in some cases the artist proofs are created after the edition numbers have sold out. Must bear the artist's signature or mark, and, since the early 20th century, is usually numbered as part of a fine art edition and should be limited to two per edition.

Base
Also called plinth. The base is what the sculpture is attached, fixed or mounted on. A block (of any shape or dimension and material placed between a sculpture and its pedestal). These terms can all be confused as a pedestal is also defined as a base or foundation.

Blown Glass
Glass made from blowing a glass bubble on the end of a hollow tube. An artisan may then shape it by spinning, rolling and pinching with iron tools to make a vase, bottle, glass or other object. Alternatively, the bubble may be placed into a hollow mold and further blown until it expands into all of the details of the mold.

Bronze
An alloy of copper and tin, sometimes containing small amounts of other elements in varying proportions such as zinc, silicone and phosphorus. Harder and more durable than brass and used extensively since antiquity for casting sculpture. Bronze alloys vary in color from silvery hues to rich, coppery red. Different countries have different standards for the mix - and mixes also may vary from one foundry to another. In its molten form, bronze is poured into the main channel or sprue of an investment casing surrounding the wax of a sculpture to produce the final cast piece of artwork. Dimensioned bronze sheets can also be used to fabricate sculpture.

Casting
The process of making a mould (plaster, or rubber, polymer and plaster, etc.) from an original, then creating a wax, investment, and pouring molten metal. Generally bronze but also glass, aluminum, iron, or stainless steel. Precious metal (silver, gold, and platinum) are also cast.

Conceptual
Conceptual art is art in which the concept(s) or idea(s) involved in the work take precedence over traditional aesthetic and material concerns.

Coil Building
Coiling is a hand building technique used to make pots. Plastic ‘snakes’ of clay are used. They can vary from a thin strip to a large sausage like strip. It is hand manipulated, pinched and squashed together to form a pot without the coil like look from how it was started, though in some cases the clay can be left snakelike for the decorative look. Typically this is started at the base of the pot and built upwards.

Cones
Pyrometric cones are composed of clay and glaze material, and are designed to melt and bend at specific temperatures to determine the conditions of a kiln. Cones are a better indicator than temperature alone as the degree of glaze melt is a combination of time and temperature heat work. A fast firing needs to go to a higher temperature to get the same results as a slow firing to a lower temperature. Low fired ceramics are generally fired to Cone 1 or 2, high fired can go to cone 6 to 10.

Core
In sculpture, the core is the solid internal portion of an investment mould for casting a hollow piece of sculpture (such as a portrait). The amount of space left between the core and the mould (occupied by wax before it is "lost), determines the thickness of the cast metal. The core is made of foundry sand (can also be same as investment material) in sand casting and in the lost-wax process.

Figurative
Of or portraying the (human or animal) figure. Figurative sculpture can be either realistic (in varying degrees...) or stylized.

Firing
Exposing to heat in a kiln a clay body to harden it or an investment casing containing wax so as to "lose it" which is an integral part of the lost-wax process . See Foundry.

Foundry
The building or place where the casting of bronze takes place by the lost-wax, sand casting or ceramic shell processes. Typically a foundry will have subdivisions of activities taking place. Most often these break down to mould making or the making of a negative container, then the pouring of wax into the moulds, cleaning up the seams from the wax, then making a core, spruing and gating the wax cast of the sculpture with wax strips or rods (sprues and gates) which will ensure the smooth arrival of the molten metal into the negative space formed when the wax is "lost", encasing the entire piece into an investment, then "losing" the wax out of the invested piece by firing it, finally pouring the molten bronze into the main sprue, hacking away the investment material, cutting off the bronze sprues and gates, chasing away any other unwanted bronze (or filling in any holes), chiseling, and then either polishing, or applying a patina and or wax to the sculpture. Mounting the final piece on a base is sometimes also an intricate part of the foundry's work. Foundries will often assist a sculptor with the installation and securing of large pieces.

Gate
In casting, any of the several channels or ducts through which molten material is carried from the main channel or sprue, to the hollow part of the investment mould or casing and through which the gases escape. The waste piece of material formed by such a duct is also called a gate, and is removed from the cast metal along with the sprue as the first stage of cleaning up the sculpture. A gate is also sometimes called a runner.

Glaze
A layer of ceramic or glass that is fused onto the surface of the clay of a pot or ceramic piece. Used to seal the piece, decorate it, or both.

Installation
Refers to a type of sculpture that consists of a group of elements needing an environment, also the term used to place and secure a sculpture.

Investment
A containing negative mould, used in sculpture for casting metals. It consists of either earth clay and sand or plaster of Paris mixed with clay, pulverized plaster, asbestos fibers and glue size when mixed up for the lost-wax process. Also sometimes called casing. The wax is dipped separately into baths of different density to create the investment. After the wax is burnt out, the investment receives the molten metal.

Kinetic
Art that incorporates actual movement as part of the design.

Limited edition
The set number of replicas or copies a sculptor plans to make or has had made from an original, after which the mould is destroyed. The practice of limiting editions and numbering proofs originated with etching and drypoint, in which the quality of the proofs declines as the copper plate begins to show signs of wear. By thus limiting the size of an edition to first-rate examples of a sculptor's work, the sculptor protects his or her artistic integrity and the value of the works to the collector. There is no technical reason for limiting or numbering editions of works of art that are made by processes capable of turning out an indefinite number of uniformly good copies, such as lithography or casting methods that employ durable moulds - and in any case a new mould can be taken from the original to extend an edition (if not limited). Editions are frequently limited however for financial reasons; by ensuring the relative rarity of the sculptor's work, he or she increases its value. In Europe, fine art editions are generally limited to a max of 9, in the US, to a maximum of 12, plus 1 or 2 artist proofs and occasionally 1 or 2 foundry proofs.

Mixed Media
The term is generally used when two or more media are used in a single work of art, e.g. metal and wood, or metal, wood and stone. Mixed media include plastics, fibers, and any man-made or natural element that can be used to model or otherwise construct a sculpture.

Medium
Referred to as the material used for a given sculpture. Bronze, terra cotta, plaster and steel are all examples of media.

Model - Modeling
The process whereby a sculptor adds wet clay or other soft medium such as wet plaster or cement or other media to build up or construct his or her original artwork - often using an armature. It is essentially an additive, not a substractive process as contrasted with carving, though substraction can also be and is often used in the process of achieving the desired shapes.

Multimedia sculpture
Multimedia is media that uses multiple forms of information content and information processing (e.g. text, audio, graphics, animation, video, interactivity). Similarly to mixed media art, the artist can combine a number of media in three dimensions to create a sculptural work.

Patina
Patination is enhancement of bronze by the chemical application of color. Three water soluble compounds form the basis for most patinas: Ferric Nitrate produces reds and browns, Cupric Nitrate creates the greens and blues and Sulphurated Potash produces black. Each foundry develops its own proprietary (and carefully guarded) patinas that result from a carefully orchestrated blend of different chemicals, pigments and application technique. Wide ranges of colors, both transparent and opaque, are available to the experienced patineur. The final step is putting a thin coat of clear wax over the bronze to enhance and preserve the patina.

Relief
In sculpture, any work that projects from the background. Reliefs are classified by degree of projection. Relief sculpture is distinguished from sculpture in the round. In a bas relief the figures project only slightly and no part is entirely detached from the background (as in medals, coins, or areas of large reliefs in which the chief effect is produced by the play of light and shadow). In a haut relief sculpture, the figures project at least half of their natural circumference from the background. Between these two is the demi relief (half-relief or mezzo-relievo). The lowest degree of relief in which the projection barely exceeds the thickness of a sheet of paper is called a crushed relief. There is also a relief in reverse, called hollow relief, in which all the carving lies within a hollowed-out area below the surface plane, and which, through an illusion of depth and roundness, looks like raised relief. Reliefs may be carved from hard materials or modelled in wet clay, softened wax, or plaster. Reliefs are often elements of architectural sculpture.

Slab Building
Clay slabs are cut to shape and joined together using scoring and wet clay called slip. Slabs can be draped over or into forms, rolled around cylinders or built-up into geometric forms. Large forms are difficult because of stresses on the seams and because the slab naturally sags. Some potters get around this by working fibers into the clay body. The fibers burn out during the firing, leaving a network of tiny holes.

Sprue
In casting, the entrance hole and main channel in the wall of a mould through which the liquid material (bronze or other metal) is poured; it is joined to the model by smaller channels called gates. The waste material formed by the channel is also called sprue and is cut away after the investment material is removed, as the first step of cleaning up a cast metal sculpture.

Welding
The process of joining together two pieces of metal by fusion. Intense heat is applied by an oxyacetylene torch in gas or oxacetylene welding, and by electrical means in arc welding. Sometimes a filler rod is melted along the joint, in the process known as brazing. The direct welding of two pieces by combining the molten edges is called fusion welding. It is done at much higher temperatures than soldering and results in stronger, more durable joints. It is used in making direct metal sculpture and comes under the general term of assembly - as opposed to carving and modeling.