Additive: An action that produces addition of some materials. Often refers to modeling. Materials especially appropriate for additive sculpture in schools include clay and wax.

Armature: A skeleton-like framework to give rigid internal support to a modeled sculpture, typically of either clay or wax. Wire used to build an armature is available in various gauges. A basic linear form in wire can be made with chicken wire or padded with wood or paper if appropriate. The medium is modeled directly onto the armature.

Assemblage: Creating sculpture by combining many elements—especially found objects—into a complete work of art. The work is "assembled" from many parts.

Bisque or bisque fire: The first fire of ceramic clay. Bisque ware is generally unpainted clay that has been fired once.

Bronze: An alloy of copper and tin. It is a strong, hard metal used in cast sculpture.

Bust: A portrait sculpture or a painting representing a person's head, neck, shoulders and upper chest, and perhaps the upper arms.

Cast: To form materials (i.e., molten metal, liquid plaster, or plastic) into a three-dimensional shape by pouring into a mold; or something formed by this means. Also, an impression formed in a mold or matrix. The original piece is generally made of a less durable material than the cast.

Ceramics: The art of making objects with clay and firing them in a kiln at high temperatures to make them harder and stronger. Types include earthenware, porcelain, stoneware, and terra-cotta.

Clay: Mud; moist, sticky dirt. In ceramics, clay is the basic material, usually referring to any of a certain variety of mixtures of such ingredients—fine-grained, firm earthy material that is plastic when wet, brittle when dry, and very hard when heated. The most common types of ceramic clays are earthenware (terra-cotta is an example), stonewares, and porcelain. Also, a hardening or non-hardening material having a consistency similar to clay, often called modeling clay or Plasticine.

Construction: A term referring to a sculpture made by joining together various components of different materials or materials of the same substance.

Environmental art: Related to assemblage; uses large elements that can be experienced by walking through and around the work. Environmental art frequently incorporates found objects as well as painting and sculpted forms.

Found image, or found material, or found object: An image, material, or object not originally intended as a work of art, which is obtained, selected, and exhibited by an artist, often without being altered in any way.

Free-standing: Sculpture surrounded on all sides by space.

Frieze: A band of relief sculpture attached to a wall.

In the round: To be viewed from all sides; free-standing. When referring to sculpture, a type that is surrounded on all sides by space. The opposite of relief.

Maquette: A small model (usually in wax or clay) of a larger sculptural work. The maquette is used to propose a large or monumental work to the client for approval before the major work is started.

Mobile: A balanced arrangement of thin rods or stiff wires with objects suspended from them. The entire sculpture hangs from a filament and is moved by air currents. 

Modeling: A sculpture technique in which a three-dimensional form is manipulated in a soft material such as clay—either modeling clay (Plasticine is a well-known brand) or ceramic clay—or wax. The term also refers to the effect of light on a three-dimensional form. The three-dimensional quality of such a form is emphasized by means of light, shadow, and color. Reproducing the effect of light, shadow, and color in a drawing of such a form makes it seem more realistic. 

Mold [American spelling] or mould [British spelling]: A hollow or negative container that gives its form to a substance poured into it. The substance—such as clay, plaster, plastic, or molten metal—is allowed to harden to create a sculpture. A typical mold is made by coating an original clay or wax sculpture with plaster and removing the dry plaster piece. The mold is put back together and a substance is poured into the whole mold. 

Negative Space: The empty space in and around an object that helps define the sculpture.

Papier-mâché [pr. American: paper mah-shay', French: pah"pee-yay' mah-shay']: A French word, literally meaning "chewed-paper." The equivalent Italian term is cartapesta. A material, made from paper pulp or shreds of paper mixed with resin, wallpaper paste, or flour and water (2:1 by volume). Papier mâché can be molded or modeled into various shapes when wet and becomes hard and suitable for painting and varnishing when dry.. It is known to have been used for low reliefs in Italy in the fifteenth century, and was occasionally popular in Europe for ornamental furniture. Celluclay is a powdered-paper product for making papier-mâché.

Patina: A film or incrustation, usually green, that forms on copper and bronze after a certain amount of weathering and time. It is usually a result of the oxidation of the copper.

Positive space: The space a form occupies in an artwork. The actual material of the sculpture.

Relief: a type of sculpture in which form projects from a background. There are three degrees or types of relief: high, low, and sunken. In high relief, the forms stand far out from the background. In low relief, also known as bas-relief, they are shallow. In sunken relief, also called hollow or intaglio; the backgrounds are not cut back and the points in highest relief are level with the original surface of the material being carved

Sculpture: A three-dimensional work of art, or the art of making it. Such works may be carved, modeled, constructed, or cast. Sculptures can also be described as assemblage, in the round, and relief, and are made in a huge variety of media.

Statue, statuette, and statuary: A three-dimensional form of a person or animal that is sculpted, carved, modeled, or cast in any material; usually an entire figure. It is used to describe a figural sculpture in the round rather than in relief. "Statue" is not a synonym for "sculpture." A statuette is a small statue. Statuary is a collective term for statues; a group of statues. It can refer to the art of making statues, and is also a rare term for a sculptor. Statue comes from the Latin word status, meaning position or state. 

Subtractive: An action that produces subtraction, or the removal of some materials. Often refers to carving. Materials especially appropriate for subtractive sculpture in schools include clay, chalk, plaster, soft salt blocks, artificial sandstone, soap, and wax.

Three-dimensional: Having, or appearing to have, height, width, and depth. 

Examples of Materials Used to Make Sculptures

wax
paper (i.e., papier-mâché, cardboard)
clay
stone (i.e., marble, soapstone) 
wood
metal
wire
plaster
foam
plastic (i.e., resin)
fabric
found or ready-made objects